My phone got very hot for about 15 minutes last night and started dropping power pretty fast. Other than I've noticed it gets warm more often than 7.1.1
Was wondering if that was just me, too. iOS 8 B1 and iOS 7.1.1 rarely ever got hot for me. Now, my iPhone 5s is getting quite warm even with not very intense use. Clean installed and restored as new once more just to make sure. Gonna pay attention to see if it occurs in B3.