I'm experiencing:
1) the faster battery drain,
2) slower charge,
3) negate charge while in GPS,
4) MASSIVE amounts of lag (sporadic),
5) I've also noticed that I'm booting with far less available memory than I used to (according to ATK it was 2.1: about 180-200MB free; 2.2: about 110-140 free).
6) VZNav and AmazonMP3 are constantly opening themselves (and I don't wanna hear that they aren't slowing things down. I experience lag, they are open. I kill them, lag goes away.)
For the record, I went with the update.zip method
Long story short, I was under the impression Froyo was supposed to make my phone faster and more efficient. It's made it slower and less efficient. HTC/VZW's Froyo update sucks. I'm considering a hard/factory reset right now. After that, Rooting. (in case of warranty needs, can you unroot?)