The DK28 build is pretty darn good, with two issues I've noticed. The first is the home screen takes FOREVER to draw the icons/widgets going from landscape to portrait on occasion. (Other times its fine, just sometimes takes what seems like forever...several seconds easy).
The second is that my BT Car-kit doesn't seem to have audio any longer. I can hit the green button to pick-up, but can't hear the calling party, nor can they hear me. Might be that I need to re-pair the two with Froyo or some setting in the Parot car-kit. - Still investigating.
Battery wise, it seems even better than 2.1...now, I was running an under-volt and overclocked kernel with 2.1, which uppped the battery time over stock. I'm on the stock DK28 install, other than being rooted for Titanium Backup and this thing seems fantastic! My meter is still showing FULL and its been off the charger since around 8:45 this morning (now around 5:00pm) and I've had a couple conversations, sms, email and a brief browsing session or two. - Why are others saying the battery life is lower? (Are you waiting to check battery life until AFTER the phone finishes syncing with the mothership? - The Market takes time to sync up the apps that have been restored).