How is your experience running iOS 8 on an older (non-iPhone 6) iPhone? I only had it on my iPhone 5s for two days before picking up an iPhone 6, but my experience says iOS 8 is a bit of a battery hog. Or, ‘chatty.’ Gordon Kelly found similar issues:
Reports of this nature are not unusual with iOS updates. Apple’s control over hardware and software is typically cited as a major advantage for its fast and reliable iOS roll-outs, but there are still millions of variables such as app combinations and settings which can play havoc
iPhone owners running iOS 8 will need to check apps more carefully for usage, but that’s easier thanks to the ‘battery shaming’ list in Settings.