For my use, it lasts 3-4 days.
I'm not a heavy user, but do check e-mails, facebook, SMS's, use it for calls, and such things daily.
I very seldom have less than 3 days on a charge, and have had up to 5 days between charges.
The times are much better than with the original battery.
I found that following the recommendations from Mugen, regarding charging the battery when its completely new, helped a _lot_.
