Mine was significantly better. 5.1.1 gave me 5-6 hours of usage. With 6, I'd get anywhere from 7-9 hours usage. But then again, I calibrate by battery once a month and with any new OS.
Once you update, drain it to 0%, then charge it. You should notice much battery life after this. If you use it without draining, you might not see as great of bl as seen. It's best to do this once a month or with any new OS version. I've done this and have gotten great bl out of my devices.Updating as we speak. The OTA says it takes about an hour to update. Does it really take that long?