In one of those threads there was a theory that the 4.2 update required some sort of processing, or something. That the problem would eventually disappear. I noticed last night that Google Services was not my top use, or even one of the top five uses, so there apparently is something to that theory because I have not received any new updates.
To the OP, just leave the screen brightness on automatic. And give the battery time. I've never found that batteries last long on brand new devices.