I would save your money if the 360 version is the one you are looking into.
They aren't even the same game, really.
360 - Engine will be a heavily modified Frostbite ("1.5"), mapsize is much smaller or the maps will be modified and limited. Anything involving long-distance gameplay (tanks, snipers, etc.) will be different. Graphics won't be as good.
PC - Entirely new engine, Frostibe 2. None of the underlying limits of the 360 version will be present whatsoever. It really is important to understand these aren't just superficial, they will affect gameplay in either minor or major ways.
360 is getting Battlefield 3 Jr.