I agree with datlas, mostly marketing/bs. I've had pads that worked for me, and those that didn't, long (long, long...) before 3D/4D pads, and I expect to be cycling long after they're gone. It doesn't matter what they're called, as long as they work for you. Unfortunately, once you do find a pad that you really like, it'll probably be changed next year (or certainly by the year after that).