Whatever rom you're on, you chose it for whatever reason and you like it.
For battery life, I believe the most influential thing is the kernel. It controls the clockspeed and voltages among many other things directly related to battery.
This is just my opinion, but I think with some kernels, the dev keeps pushing out updates at an accelerated pace just for the sake of updates. People clamor for updates. Sometimes they go backwards and battery life worsens, so they push another update to fix what was fine in an earlier version.
I am running heyitslou's defiant V3 kernel for over a week now, with excellent results. It's a very basic kernel as far as user input is concerned. No overclocking options or undervolting stuff. Also very limited governer options. He says to run it just as installed. I'm convinced there are savvy underhood tweaks that optimize battery life. I'm done with the kernel flash every couple of days. Doesn't make sense to flash something new to go backwards.