I have had the Eris since day one along with the Motorola Droid. The battery on the Eris was so sub par, it drove me nuts!
Since the update, I can get through a whole day with no problem. Power management seems to have been covered in this update.
The one gripe that I still have with the Eris is that the default Youtube appliation consistantly tells me that it cannot play a video. I gave up on that application and now just go straight to Youtubes.
