yeah sometimes even more, my moms 820 gives her a battery life of a day at max like extreme usage
mine can even go upto 2 days sometimes
both on 3G and wifi and even bluetooth turned on nearly all the time even when not in use
did u install any apps to monitor ur battery life? they are pretty good usually and give stats of other users of the same model as u as well(cant remember the apps name but there are many similiar ones,have tried 2-3 of them)
even weirder thing is the 720 is essentially a slightly turned down 920 and stuff,should have given smiliar batter life maybe the cpu,camera,ram etc are better so they drain more juice