Battery use on E90 (210.34.75) is excellent! I can't say that my time-to-charge is less now, with my phone already checking 2 IMAP boxes and downloading weather updates, which basically keeps EDGE running 24/7.
One question: after a long voice call, or, sometimes after the phone sits with zero service for a few minutes, the built-in application does not always "reconnect." This seems sporadic and I--so far--cannot find a pattern based on whether the built-in client front-end is "running," or, is silently in the background. Any experiences from users that frequently go into low-service areas?