mobile

Hi, since there are a lot of roms out there, I would like to know how to differentiate all these roms since the vast majority of them are based on cm12... Which rom is the smoothest? Which rom has the higher battery-life? Which one have the more functionalities? Which one compiles buttery-smooth performance, awesome battery life and a lot of USEFUl functionalities? I am currently using lollipop-stock root rom, with x-posed. I love the stock camera-app, but I experience lags, battery isn't as great as on kitkat, still 5.0.1, and random reboots every two-days,....