IE 9 was released in March and IE 10 already in preview release scheduled for Sept. I designed a site around Chrome-dev (13, now 14) and it looked better in IE 10 than in FF4/5. The IE release cycle is definitely not ideal but a 6 month release cycle is a god send.

IE9 is acceptable and IE10 is surprisingly good. I have a feeling the IE team is targeting WebKit as their competition and not FF.

I haven't liked IE best since IE5, long time Firefox user from Phoenix 0.4, but I'd really suggest trying out IE10, it's pretty much on par with FF4 stock from everything I've seen. I still really don't like that it doesnt handle tab closing properly (IE10), but I see that FF5 finally handles tab closing half way decently. Tab handling and the 'awesome bar' or whatever the Chrome team calls it were the biggest drivers of me switching to Chrome. Also, IE10 now has a single URL/search bar which is a vast improvement and puts it on par.

It's the stable version that matters, not preview one, since preview versions don't get pushed to users, and it's only a very tiny amount of people using them. Microsoft thinks in 1 year cycles, Google and now Mozilla, too, think in 6-8 weeks cycles of releasing stable browsers with new features. IE will give new features only once per year to most users.