I know Firefox has worked on their speed, and it may be I only notice a difference because I'm on a netbook, or because the Firefox versions of my extensions are more poorly written than their Chrome counterparts. But for whatever reason, Chrome feels faster to me--both in general, and also due to other nice touches like its ability to open PDFs without launching Acrobat.
The window-dressing is nice, but just as search quality is the most important thing in search engines, and auto-complete, instant search, etc. are mostly secondary, speed to render the site appropriately is the primary indicator of browser quality; new-tab windows and the like are nice-to-haves. As far as I can tell, Chrome is still winning on speed, and I hope Mozilla is devoting appropriate resources (read: 90%) to changing that.
EDIT: as an aside, I know downvotes are somewhat amorphous on HN, and I shouldn't take them personally, but it bugs me that when I take some time to try to write a thoughtful (though admittedly critical) reaction to news, I get voted down to -1 (at least 5 downvotes) for my trouble. I've seen similar reactions frequently in other threads, and it saddens me that this is apparently now common HN behavior. This response is just not conducive to building a community. The responses here are great--if you think my comment is wrong, upvote those instead. Meanwhile, excuse me while I leave HN...