After using Firefox 2.0 for a few days, I have the following to say:
1. It's not much different from 1.6, however, my general feeling is that it runs a bit faster.
2. I'm somehow upset that some of my extensions (add-ons) did not get updated yet, but I know this is not Firefox fault. For example, I run SiteBar server and use the extension to get to all my bookmarks from any computers I use. SiteBar is great, but it is still not working in 2.0, so I'm stuck with regular bookmarks, which is not fun.
3. I have not had any crashes yet, which is a good sign, given the fact that it is version 2.0 (zero, being always buggy in my mind).
So far so good Firefox. I'm sure I'm not going to travel the IE 7.0 road anytime soon... :-)