Well, I just switched back to FF2 after less than a week with FF3. Apparently, I have too many bookmarks for the fancy new FF3 sqlite bookmarking system. FF3 was dog slow adding bookmarks and bookmark folder. Literally, 10-20+ seconds waiting for the list of bookmarks to load. There aren't enough hours in the week to wait that long for every bookmark. I was tempted to make a little video of the how slow it was and put on YouTube. I spent the week trying every tip, tweak, addon and about:config setting to fix it, but couldn't get a reasonable level of performance.
I thought, maybe I was imagining how snappy FF2 was, but when I rolled back to FF2 it was fricken instantaneous. I can't believe I thought I could put up with FF3's sluggishness. And actually, I exported my bookmarks out from FF3 and re-imported them back into FF2.
I also had some extensions that aren't working or aren't working the way they used to, so that compounded the problem.
Otherwise, I had mostly disabled all of the new "features" in FF3 in an attempt to get back to FF2 performance. Most of them just added unnecessary extra clicking and scrolling in return for less information on the screen.
So, I'll probably wait until they EOL security fixes for FF2 before I try FF3 again. Hopefully, they will have worked out all the issues by then and the addons will all be updated by then. If they don't fix bookmarks, I really hope someone comes up with an addon that entirely replaces the new bookmark system with the old one from FF2.
I feel like a Vista user switching back to XP, except in my experience Vista isn't as bad (I still keep Vista64 on one dual-boot machine).