The only thing i noticed was that the first week, it took a while for the phone to settle down. This wasn't explained very well anywhere. Now, my phone, like others mentioned, with moderate use, usually gets put back on charge with 65%-75% charge remaining. With heavy use (where's my water drains the battery quite hard) then it will go lower. I'm yet to get the phone critical. Yesterday, i used it a fair bit, updated the phone, which used a lot of battery power to do so, and used the phone with high brightness (took me a while to realise) and it was at 30% remaining charge.
My previous android phone (SGS1), with battery bugs, it would regularly not survive. When it would decide to crap itself, which was almost a daily occurrence, it would go through a full battery in about 6 hours whilst doing nothing, just in my pocket with the screen off. Battery use had to be monitored, and pulling the battery out to reboot was almost daily. There were numerous times where it didn't last the day, and it was very annoying.
I really like the battery conservation feature in WP8, which allows you to engage until next charge. If you know you're in for a big day, and need your phone to last, this is quite useful, and a really good function in the phone.