I ordered 2x Ghost (1 for PS4 and 1 for Xbox One), and 2x Limited. Why? Because I can't make up my mind on what edition I want, or what console I want it for. I figure I'll cancel 3 of those orders closer to the release date.
Unless they require you to pay in full, I'd recommend doing something similar if you can't make up your mind. They seem to be selling out rather rapidly. Since Best Buy just requires an authorization, I don't see it as a big deal.