I think there is some battery improvements ater the update. My phone today was 100% full 7 hours since last charge. i cant imagine the improvements we shall get after cyan update
Looking at "Battery Saver" before and then after U1, I noticed it was Skype that was eating my battery prior to U1 in the background. Now with U1, Skype is low on the battery consumption list and now my battery lasts quite a bit longer
I think the trick is to make sure that you hard reset your phone after getting the update. Then you set your account and install your usual applications. After doing that even heating is gone for me.