HTC One all the way. You won't bring it back 
Battery life, no problems at all. When at the office/home, switch on wifi and it will conserve less battery (like every other phone). Unlike other phones though, I'm sometimes able to go for 2+ days without charging.
Also guys, try switching the power saver setting off and try it a few days. See if it can go longer. It can. From what I recall reading somewhere, that setting basically caps the CPU at 3/4 or so of its capacity - when isolated, that saves power. In the hands of an average phone user with a bunch of different apps though, it actually has the opposite effect because those apps, in turn, are forced to occupy the CPU longer.
The battery life is great. The phone is awesome.

Battery life, no problems at all. When at the office/home, switch on wifi and it will conserve less battery (like every other phone). Unlike other phones though, I'm sometimes able to go for 2+ days without charging.
Also guys, try switching the power saver setting off and try it a few days. See if it can go longer. It can. From what I recall reading somewhere, that setting basically caps the CPU at 3/4 or so of its capacity - when isolated, that saves power. In the hands of an average phone user with a bunch of different apps though, it actually has the opposite effect because those apps, in turn, are forced to occupy the CPU longer.
The battery life is great. The phone is awesome.