I've flashed nearly every rom made for every phone I have owned. Right now I am on Malladus 1.2.0. I have been off of the charger with light to medium usage for 8hrs and 23 minutes. This consists of a few calls, some web browsing, emails, etc.... I still have 96% of my battery available. This is absolutely ridiculous! I definitely recommend this rom if you like the stock LG launcher with some tweaks.
One thing to note, I am running the snapdragon battery guru app as well, though it is in the learning stage. It shouldn't have any effect on the phone right now.