it's more of a personal preference.
it's like black magic.
It's something you need flash and understand.
p.s. - back in the kitkat days my oneplus one with a wicked crazy mahdi rom and a soulful Franco kernel used to fetch me 7-9 hrs SOT with 3-4 hrs of Voice calling.
I called it 'black ****ing killer magic'. moreover it's always been flash and forget.