According to many, many posts on apple's forum, 2.2 destroyed battery life. Many are reverting to 2.1 until 2.3 comes out.
I still may buy it on Black Friday, if the price is 15% off as some speculate, or wait until Dec 28th when they are in WalMart and Sam's.
I really like the aviation application, something that WM does not have. The screen is big enough to use in the cokkpit(had to spell it wrong to post) as well.
http://www.foreflight.com/