Just thought I'd share my 2.2 update experience. After the first update, when I opened the app tray, it would only list 1 page worth of apps (alphabetically), so either the rest weren't there, or the scrolling didn't work. After the 2nd update (FRG22D) which I forced yesterday, this hadn't changed so I finally gave in and tried a factory reset. The good news is that it worked and I can now scroll through all my apps in the app tray.
But it didn't come without a price , and there were some minor inconveniences and annoyances that came with the factory reset (not counting having to re-synch accounts, and reset ring tones, etc.).
1. I lost BitBlocks, which was a tetris like game. I didn't know that Google had removed all unofficial Tetris games from the app store so that only the official one (which I've read isn't that good) would be available. So when I did the reset and my phone started to re-download all my apps, this one wasn't there any more to be downloaded.
2. On Toss It pro, I lost my records (I was up to 300 on one of them), and on Raging Thunder, I lost all my unlocks (stages and cars) so I have to go through that again (but that's not so bad since its a fun game). Luckily, all my Robo Defense data was still there.
3. After the first update, I wasn't getting 3G at work for a week but I assume it was a Verizon thing since I got 3G in other areas, but its happening again after the 2nd update, so I'm not sure what to think.
4. I noticed if I turn the phone off, that when I restart it, the wall paper switches back to the standard Droid wall paper it had when I first got the phone (I normally use Aquarium live wall paper). It just takes a few seconds to reset it, but like I said these are just annoyances and inconveniences, nothing major.