There's a disable LTE option in the cellular menu.
I also noticed my battery draining quickly yesterday...went from 90% out of the box at 2:30pm to shutting off at 9 pm. I charged it uninterrupted overnight, so we'll see how it does today.
I know disabling the LTE would help like disabling the 3G on the other iPhones. But what's the point of having a LTE phone if your going to constantly be turning it on and off? That defeats the purpose. Why buy the phone then. I'm willing to bet the new iPhone will still have mediocre battery life
James