I got my 2150 mah battery in the mail the other day and let me say WOW what a difference in battery life! On a normal day, i make/receive a dozen phone calls, send/receive 50 emails, spend a couple hours each on meebo IM, pandora radio and general web surfing. I fully charge before i go to sleep, so by midnight i have a topped off battery. By 5pm the following day, normally i'm in the yellow on the battery meter. Using the extended battery, i'm on day two of this usage pattern, without having charged last night, and the battery only just hit 50%! ~40 hours of uptime 8 hrs and 35 minutes of awake time Voice calls, Display and Android system have eaten the lions share of the battery. I'm very impressed. Once i break the battery in, i might be able to get 3 days out of it.