We already know that there is no "BEST ROM", but I'm gonna read it as "recommend me a good rom"!.
Quick and fast: NONE.
Anything over 4.1.2 is laggy and slow. May be better or worse, but nothing does in performance and battery like a good stock-based 4.1.2 ROM.
Also CM roms have (or had) worse gpu performance than stock roms.
I have tried a lot of roms, either stock and CM/Omni based, and I finally kept with Imperium 13.6, located there:
Again, it's just my opinion,