I must be an oddball...my iPhone is getting several extra hours of charge since the update.
I can't say one way or the other... I updated my iPhone 4 yesterday afternoon and last night I walked into Best Buy to find they had received 20 iPhone 4S just 20 minutes before... so I upgraded. They bought my 18 month old iPhone 4 for $180, and my total out of pocket cost to upgrade was $70.01. . . plus a new two year contract. So I had iOS 5.0.1 on my iPhone 4 for about six hours before it was gone, out of my hands. The new iPhone 4S has not needed a charge... but I don't have a baseline experience to judge it by.