Opera

I'm a computer technician, I've used many browsers with many types of computers, mac/pc/ and linux. Basically what it came down to is chrome, Firefox, Opera, and even Safari all ran about the same, but when I turned on the "turbo" (image compression), it ran the fastest on all my computers. The only one that that was slow was Explorer, which is built for safty more than speed.

*on linux OS, Firefox was the fastest

I recently tried using Opera again. It's better than I remembered, but the lack of good addons and extensions for Opera is crippling. You can block ads on Opera with addons, but that's about it. The reason I like Firefox and Google Chrome so much is because both of the browsers are incredibly extensible. In that aspect, Opera has a long way to go.

As for the browser itself, Opera is actually very good. I recommend using the "Z1-Glass" skin if you're using Opera on Windows 7; it looks totally awesome. Additionally, the browser has a couple of very nice built-in features. For starters, Opera Unite seems pretty useful, though it wouldn't replace Dropbox. With Unite, you can download any file from your home computer remotely from another computer running Opera. And Opera Link synchronizes your bookmarks between computers, which is a must-have for anybody with multiple computers. However, Xmarks and Chrome both do a better job of this; Xmarks supports syncing between multiple browsers, while Chrome syncs extensions and browser preferences, along with bookmarks.

Opera is portable (native --> from the developers);

Opera is incredibly customizable (which means you can use it both at home on your big screen or on the move on your netbook with more adequate configurations for each --> easy);

Opera has it's own sync features (which means whatever you browse and bookmark at work on your profile - or on your 2nd computer - gets automatically syncronized at home --> powerful);

Opera has built-in mail and feed reader, chat client and so much more... I can't praise it enough.