I haven't followed AT&T much but I doubt the 1520 drops down to a penny by Black Friday. Either way, some people don't care. If they want something now and can afford it, they get it.
To answer your question, I personally have never been the "pre-order" kinda guy. I just get it when I can. If it sells out on the first day, I'll just wait. I do get why some people pre-order something. They are excited about a product and simply want to get their hands on it as soon as they possibly can and pre-ordering it ensures that they do.