If you back up you can always restore and you'll be okay. But a couple things to consider about the 2.2s out there. There are some bugs still in them but see what the bugs and and if you use that feature. I think it's USB mounting, mms, and camera but I'm not 100% on those. The latest rumored date (when it comes out I'll believe it's out) is Monday the 28th, so you may want to wait a couple more days and see.
Another option you have is Icarus 1.1 (I'm using it). And since it is basically a streamlined version based on the official 2.1. It's got all the bloatware removed and some improvements. Icarus has one MAJOR advantage (if you have a lot of apps) and that is it's a2sd. Now Froyo does support Apps2sd but only if the apps are designed for it. But a2sd moves all of the apps onto your sd card because it "tricks" the phone into thinking they are in the phone not on the card. It will also put your Dalvik cache on the sd card too (you have to manually do that though) to free up even more memory.
Good luck on whatever you decide
P.S. I may try the Official 2.2 but I will probably go back to Icarus until someone tweaks it.