Stock ROM is having very good battery life but bad camera post-processing quality.I also bought this phone last month, and trust me bro Its awesome..........except for the camera.
Camera is just average and it sucks me all the time. But
But the battery is aweome. I can watch movies or videos on it for continous 7 hours
and on heavy usage it can give 5-6 hours easily.
When you use it averagly it gives batterly life of about 13-14 hours.
May be you have kitkat version, that sucks. Dont use kitkat firmware. Stick to jellybean 4.1 or 4.2.
They are best, fast , stable and max battery
AOSP is having okay battery life but good camera post-processing quality.
Choose.