I had a huge battery drain day 1, no problem today, but it is beta after all. I've narrowed it down to either Music being on all day, The Guardian, or playing candycrush on the head.
If you want out, just put it into Recovery mode, plug into iTunes, restore to factory, restore to the backup you took before you upgraded to 7.
Recovery mode instructions here: http://osxdaily.com/2011/01/08/iphone-recovery-mode/
I've done this as I forgot to register my phone as a developer device, before install! It works