Re: Battery life of HTC one
You *will* be disappointed if you are a heavy user? Seems that on their continuous usage tests it matched anything else (apart from the Maxx, of course). They claim it's the standby was "weak", if you can call 48 hours including 2 hours of calls and 4 hours screen on "weak", so surely the heavy user is least worried?
But the devil is in the details. I know that GSMArena test screen-on usage at a fixed % brightness, so phones with brighter screens are at a disadvantage (to contrast, anandtech set to 200 nits for their tests, so same light output for all devices). I don't know what they let synch in the background for their standby tests - the safest would be to either have standard apps, accounts and settings or turn everything off, but I don't know whether they try to standardise or if so how hard they try.
So I'd say read a range of tests, try to work out what they test, and look at the range of results. And perhaps more usefully, see what the real experiences of people who own the devices are.