After I wrote my previous reply, I went over and did the
Acid3 test. I first did it with my usual stuff open, and later on with everything closed but one browser and the one tab used to test. None of the browsers have any "addons" or modification except Opera, since that's what I use. I kept only the best result from each.
And the result...
Test notes: I had a few cases where Chrome stopped before reaching 100/100, spewing up 2 errors, but only for a few attempts. With Firefox, it sometimes got an error less (kungFuDeathGrip). Both Firefox and IE always failed. Opera didn't fail once, but sometimes stopped on page request (not part of the "test", probably a beta bug). I ran approx thirty tests with each browser, except IE which only got six chances.
You can try these too if you want, however these results are far less interesting to compare, as they will turn up just about the same each time.