I downloaded it at 11:30pm BST yesterday, an hour before its advertised 16:30pm PDT launch.
So far, I like it. I like it a lot. The menus seem more logical, the look-and-feel more professional and clean, and it has some nice new features, including remembering form completion, useful for my site users (who used to lose a comment entirely if they didn't pass my captcha).
There are quite a few important extensions (and less important, but nice-to-have themes) that don't yet work on 2.0. (I particularly miss the TinyUrl Creator and Fasterfox.) Hopefully they'll be upgraded soon.
I have one gripe. In 1.5, if I typed a keyword or two in the address bar (multiple words separated by spaces), it automatically looked it up in Google and loaded the first result returned. Very useful if you're confident that your keyword(s) will bring your desired site to the top of Google's listings. Not sure whether it was an extension that I'd activated, or whether it was a feature that has since deemed unnecessary. Either way, a little annoying.
Nonetheless, if you're on 1.5, I urge you to upgrade. If you're on Internet Explorer, I implore you to make the switch.
