There have been conflicting reports on the web today regarding battery performance under iOS 5.0.1, which contained a fix for the battery issue that plagued 4S users. The Apple support forums are full of complaints—go figure, but the general consensus elsewhere seems to be positive. If you have updated, let us know in the comments what your experience has been, and what changes you have made. Did you update on top of 5.0, or start from scratch? Have you rebooted, and did it help? When testing, make sure to drain your battery completely to have a fresh baseline, and mention if you have battery-hogging services like GPS enabled.