For reasons I'll explain later (if you care) I've been experimenting with the new releases of several browsers:

• Opera, version 11. Opera was probably the first browser to support tabs (and tabbed browsing). It was my favorite browser 9 or 10 years ago, until Firefox came along.
• Chrome, version 11. Chrome is the browser written by Google. (If you visit this Chrome link, be sure to click on "Learn more about Google Chrome" on the bottom right, and then on the "Visit the Google Chrome channel on YouTube".)
• Internet Explorer, version 9. Microsoft released this update recently, but it's an optional update ... it doesn't get installed automatically.
• Firefox, version 4. The open source browser from Mozilla.org
• Safari, version 5. This is the Apple browser, but there is also a version that works on a PC.

As we get older, change seems to get harder. Why would you want to change browsers? For years I've recommended Firefox and Gmail because on balance I think together they make web surfing safer. Now Gmail has almost forced me to start using two browsers at a time (see below) so I had to decide on a second choice. Major updates, which change the behavior of your current browser, may make it a good time for you to consider a change.

Bottom Line

If I had to order them today, based on personal preferences my choice(s) would be:

1. Firefox
2. Opera
3. Chrome
4. Internet Explorer

You should read all my comments below and decide which one(s) to try based on your needs. (I didn't include Safari in this list because I removed it from my machine when got rid of my iPhone and was able to remove iTunes which I hate.)

General Comments

They all talk about how much faster they are, but most of us can't see the difference. For the most part speed is a function of you internet connection. Some might have pre-fetch or compression features that make them faster in some situations, but probably not that important to most of us.

All of the new browsers have removed the Menu bar by default. Most let you turn it back on under Options, but once you get use to where the Menu Button equivalent is you probably don't need it, and it does waste space.

They've all moved buttons around which takes getting use to. Most of them have moved the refresh button to the right of the address box; I use it frequently and think it was easier to find when it was near the Back and Forward Page buttons (it's still there in Opera).

Closing the last tab closes most of these browsers. Personally I don't like that, I'm able to make Firefox stay open, please let me know how to make the others stay running if you figure it out.

Bookmarks

I like a Bookmarks (Favorites) Toolbar that allows you to get to your most frequently visited sites in one click, and an easy way to view all your other Bookmarks.

Both Firefox and Internet Explorer work the way I like. The Bookmark Toolbar is always visible and a complete list of Bookmarks is one click away (or can permanently be displayed as a list).

Opera allows you to display a Bookmarks Bar, but I can't figure out a way to import into it. It doesn't show up when you "Manage Bookmarks". My other complaint is that it takes too much effort to get your other Bookmarks: click on Menu, scroll down to Bookmarks, then move to the right so they appear. If I'm missing something let me know. Opera has a "Speed Dial" feature which displays thumbnails you can click on of sites you like to visit. You have to specify these sites, unlike Chrome which shows recently visited sites. Controlling them yourself is probably better. The Speed Dial page has an extra search box at the top which always seems to use Bing ... there is a "configure search engines" choice, but it doesn't seem to effect this box. Not really an issue, because there is a search box right above it on the Address Bar with my search engine of choice.

Chrome takes getting use to, and it takes an extra click. First you click New Tab (+) and then your Bookmarks Bar appears along with a button to press to see your other bookmarks. Update: If you right click on the Bookmarks Bar, one of the options is "Always show Bookmarks Bar"; this eliminates the extra click. Chrome also shows you thumbnails of recently used sites which you can click on.

Extensions/Add-ons

Almost all browsers now support extensions developed by others. The four I'm currently trying ALL have the WOT (Web of Trust) extension which I recommend.

Personally I really like the control "Tab Mix Plus" gives you over when new tabs are created and when focus shifts to a new tab. But this extension is only available in Firefox, none of the others seem to have this control, either in their options or as an extension.

One of the extensions I think really adds a level of security when surfing to unfamiliar sites is "No Script" which keeps Java scripts, and other things which have much more potential to cause trouble, from running until you explicitly give the domain permission to run scripts. Only Firefox has this extension. Opera has an extension called "External Scripts", but it was very annoying and didn't seem to do anything useful.

Ad blocking. This is an extension I really like when on a dial-up line ... makes surfing faster because ad graphics are not downloaded. Chrome and Firefox both have the Ad Block Plus extension, Opera has it's own Ad Block extension, IE had no matches when I searched for Ad Block.

Another Firefox extension I use is DownThemAll, I didn't find it when I searched for it in some of the other browsers. It downloads images, or other types of files, appearing on a page or referenced through links (usually thumbnails).

Opera to Phone. I need to try this Opera extension, it allows copying things to a clipboard on your Android phone. From the response to the login, I'm guessing there is also a Chrome to Phone extension. Update: It only sends a link to the currently open page and it takes several minutes to get to the phone, so don't be discouraged. What I really like is you can use Google Maps to get directions, review the route on your computer, and then with one click send it to your phone. On your phone they come up in Google Maps and with just a couple touches of the screen you're getting driving directions by voice.

Chrome

Likes / Dislikes / Features

1. In other browsers, page down (by clicking in the scroll bar below the current area indicator, or keyboard) scrolls so that the last line displayed before is now at the top. In Chrome several lines previously displayed at the bottom are now displayed at the top ... this makes it hard to find your place.
2. Has the fewest options, not counting Safari. I like options which is probably why I don't like Apple :)
3. Has a "Cloud Print" feature which lets you print to one of your printers from your Smart Phone, no matter where you are (you have to enable it in Options).
4. Has a Sync feature for bookmarks and preferences, but not for history, passwords, etc.
5. I haven't tried the Smart Phone version yet, but want to. Once I get experience with it I'll report on how well Sync and Cloud Print work.
6. Can't find a way make it save PDF files, instead of opening them, when I click on them. Neither can I control the behavior for other file types.
7. If you close the last tab in a window, the window closes. Annoys me, and makes me start it over.
8. I like the bar at the bottom that appears after you download with buttons for recent downloads and a place to click to see all downloads. I think all the browsers use Ctrl+J to show you the list of downloads ... wish they were as consistent about other shortcuts.
9. If Chrome gave me more options to configure the way I want it to behave, I would probably rate it higher than Opera, but ...

Opera

Likes / Dislikes / Features

1. Years ago Opera followed the HTML standards. As a result there were a lot of pages it wouldn't display because the developer used features the Microsoft added to Internet Explorer that weren't part of the standard. Firefox displayed most (but not all) these pages and because of this and it's advanced tabbed browsing features I started using and recommending it.
2. The new Opera seems to display most pages, just as Firefox does. However, I notice it doesn't do as nice a job spacing out tables on some of my websites as the other browsers.
3. Has the most options, but I still miss the options in the "Tab Mix Plus" extension to Firefox ... it has options I can't find in Opera.
4. It's very easy to get to recently closed tabs and blocked pop-ups. The button is in the upper right corner.
5. If you display the Status ToolBar (at the bottom) it not only shows you the Zoom level, but if you click on Zoom, you get a Zoom slider and other choices. Ctrl+Plus and Ctrl+Minus also controls the Zoom level in ALL browsers.
6. Opera has a Turbo feature (off by default) which uses a proxy server which does server-side compression of images. Websites I design already have highly compressed images, that don't benefit from compression. In fact, I've seen my images displayed on ISPs that offer a Turbo feature and the images end of looking terrible (and the user just thinks I take bad pictures). With Opera Turbo, if you want to view an image uncompressed, right-click on the image, and select "Reload Image in Full Quality".
7. Not only will Opera let me control it's behavior for individual file types (like Firefox does), but if I want to download it will let me specify different download folders for different file types which is really useful.

Internet Explorer

Likes / Dislikes / Features

1. Version 9 seems to have problems with "Refresh", if I upload a new version of a page and press refresh, it doesn't seem to always re-read the page and sub-files. If I then go away from the page and return, sometimes it then displays the new version. For me this is a real show stopper.
2. Does a much better job than it use to showing website icons on the bookmarks (favorites) list and on the Favorites Bar, don't know what took Microsoft so long.
3. I don't like the default size of the type, and they seem to have removed the option that lets you set it. All I can find is an option the specify Fonts, not the size. I recommend running displays at their maximum (default) resolution and not being able to configure the default text size in your browser is almost a show stopper as far as I'm concerned. I'm guessing that since Microsoft lets you modify text size in the Windows options they figure they don't have to give you control here, but that's not the right answer.
4. I don't really like the short address bar which by default is on the same line as the tabs. You can put it on it's own line, but personally I like a long address bar and a shorter search box on the same line ... can't figure out how to make that happen. Some of the browsers now let you enter addresses and searches in the same box, but I still think they do a better job if they know if you're entering a search or an address. I guess you can tell IE you want it to search by pressing the search icon or it's shortcut, Ctrl+E, but I still like the seperate box.
5. Extensions are a pain ... if you try to add one, the page opens up in my "default" browser (which isn't IE), but the page is designed to only work in IE. Really annoying!
6. The Bing bar (which I believe can also work with other browsers) has icons which you can add and/or remove. Since they are "active" (change to indicate updates, etc.) you may find them useful, but I would like them and the search box to be on the line with the address bar ... I don't like wasting vertical space on another toolbar.
7. Once I did install WOT, it creates a toolbar for WOT instead of putting on the address bar or somewhere else that doesn't take up verticle space. And I can't seem to drag it to the Address Bar, the Favorites Bar, or the Status Bar; only to the Bing Bar which I'm about to turn off to save the verticle space. And it seems to say that if I turn off the WOT Bar, it will turn off WOT ... NOT what I want.
8. The pull-down list that pops-up when addressing e-mails in Gmail does really weird things as you cursor down or use your mouse to choose names ... I don't see the behavior in any other browser. Makes it very hard to use. Since Gmail is one of the pages I'm always viewing in a browser, this is another show stopper.
9. I can't see any way to configure what happens when ones clicks on links to various file types (extensions). For example, I always want to save PDF files to my hard drive when I click on them, instead of opening them within a browser. Easy to do in both Firefox and Opera. I know the work-around is to right click and choose "Save Link As", but why doesn't it let me configure the behavior like Firefox and Opera do?

Firefox

Likes / Dislikes / Features

1. Firefox 4 can Sync not only your bookmarks, but also your history, passwords and even the tabs you have open on another machine across multiple machines and your smart phone. Great feature, except there seems to be a bug which started REALLY messing up my bookmarks ... must be caused by having set it up across FIVE computers and my phone ... I'm guessing it has something to do with leaving Firefox open on multiple machines.
2. With the "Tab Mix Plus" extension, I can control exactly how tabs work. None of the other browsers give me the control I want. I want links I click on that are to another domain to open in another tab and in the background; I want searches and address I type to open in another tab, but in the foreground, etc., and I want the to happen automatically without holding down Shift, Ctrl and/or anything else.
3. They moved everything around. Theory was fine, but I still find the refresh button hard to find each time even though I know where it is.
4. I like the Personas (which are now more integrated), they let you customize the look of your browser ... helpful for me when I'm running multiple browsers at once. (Other browsers call this feature "themes".)

It all started because Gmail (Google) started making their hosted domains (of which I have a couple) behave more like a standard Gmail address. Bottom line is you can't be logged into both a hosted Gmail address and a standard Gmail address at the same time ... and I always was because of the way I have setup Google Voice ... unless I have Gmail open and logged in as that user I can't answer phone calls from my computer. Turned out the workaround was to use two browsers. First I tried Internet Explorer 9, but it didn't work nicely with Gmail. Next I revisited Chrome and liked it better than the first time around. Then figured I should give Opera another try after all these years.

I still like Firefox best of all (if it would stop messing up my bookmarks).