had 4.2.2 for a couple of days now, and I can really say that the battery life is improved. I got 6 hours screen time with heavy usage today.
ughhh I need a ROM that will support wifi calling/texting on t-mobile for 4.2.2!
Also, do you use the app greenify? if you don't, you should try that and see if things improve even further. I typically greenify things like google maps, but don't greenify any messaging apps to avoid screwing it up.