What network are you guys on? A guy I work with just bought an iPhone 5 also, he said he woke up the other morning and his said it was noon and 2089 or something of that matter and the battery dies fast. He is on the Verizon network.
I have not had a single problem with mine, (knock on wood) and I use the crap out of it. Also some how my wife's 4s has fixed its self. She claims that she can go a whole day off a full charge again. We both left for work this morning with a full charge. I now have 74% and she has 26%. Even when I had my 3GS it was never that bad.