personal promise of "fewer call drops... significantly improved battery life for most customers... fixed a lot of bugs where if you have a lot of apps on the phone you're not going to get some of the crashes we've seen... backing up to iTunes is dramatically faster." We'll see.
P.S. Not that we're expecting any, but if you spot copy and paste or any other unannounced features be sure to let us know.
Update: We're updating right now and we'll let you know if we see anything amazing. Keep us posted in the comments too -- how is it going for you?