Might also want to check the actual battery usage by app. That feature comes in handy if you want to track which apps chew through the battery life.
In one 24-hour period, I saw that 96% of the battery usage occurred with one gaming app. When running that app, my battery life was probably around 3 hours. Without running that app, yesterday I saw more than 3 hours of usage, and 9 hours total, with 55% battery life left.
If anything, the battery usage on standby with iOS 8 seems to have gone down a lot, and I suspect that has to do with wi-fi calling. I'll do a more direct comparison when I have time.