Competition always sets a fire under people's butts, eh? While I was initially unimpressed with IE9, upon further review I change my opinion. Microsoft has done a surprisingly good job of getting it right up there with the other browsers in all areas. I kind of even like their Bing bar, though would never use it myself.
However, now we have the problem: Which browser should I really use? They all look very similar, perform very similar, and display sites very similar.
It is a tough call, and depends on your needs and preferences.
I will tell you one thing though, for MOBILE (e.g. Tablet) platforms *NOTHING* beats the performance of Opera Mobile (re: NOT Opera MINI). Opera Mobile vastly outperforms the stock browser in Android and even Firefox. No more of that 'undrawn screen' crap on resize or page load. It also has ALWAYS been the BEST at resizing web sites to be viewable on any screen. It does this wonderfully and was a pioneer in this area. I do not know how they stay in business at times, but we all must give Opera some major credit for creating a very compelling browser that was the first to introduce many features now common on other browsers. My old complaint (perhaps now fixed) was only having to use the 'wand' to auto-fill text boxes, instead of just have that done automatically like with other browsers.
One of the best features Opera pioneered has that nobody has done natively (though some extensions exist) is Mouse Gestures. Once you start using them, you are hooked. Close a tab by holding your mouse button and moving it a certain way, do this or that with a simple flick of your wrist. It is hard to go back to the old style of having to move to some X button ;o.
Myself? Right now I'm using Chrome on the PC and Opera on mobile devices. I may switch to Opera on the PC and see if Google service integration is better now. That was my ONLY point of contention, as the Google developers did not bother with supporting Opera (hard to blame them, it is difficult to support so many versions of IE, not to mention browsers with a low market share).