Funny, I was just thinking about posting that exact same question here. ESP? I dunno.
I've noticed battery improvement mainly due to the phone going into deep sleep. I have everything turned on and can finally get through a day without having to recharge.
The update didn't seem to improve battery life for me. Typical 8 hour day at work and when I'm done the phone is at like 30% already. Might consider just doing a factory reset again at this point to see if it helps any.