The new Firefox may not be revolutionary, but upgrading to the new version is definitely recommended.
I still haven’t made full use of its much-touted functions. I haven’t experienced any phishing sites lately. Nor have I accidentally closed any tabs. But the capability to instantly subscribe to feeds is definitely useful, and the inline spell checker is great!
It also appears that they have resolved the memory leak. It’s still a memory hog because Firefox still caches pages in memory so you can go back without re-rendering the page, but at least now I don’t see my memory counter steadily increasing.
Word of warning though. Before upgrading, disable ALL your themes and extensions. Several themes and extensions no longer work with Firefox 2.0. At first try, the upgrade process gave me a BSOD. Second try caused Firefox to hang. Only when I launched Firefox in safe mode was I able to turn-off all themes and extensions and got it to run.