I tend to like using ghillies, even if the terrain is difficult, because you CAN shoot from anywhere, and it saves you if you are surrounded. For weight and mobility, get a ghillie that just covers your back. Same effectiveness as the full suit when prone, but much lighter. It all depends on your style. If you're more of a DM, then you may want a ghillie poncho or jacket, because you'll tend to shoot from upright more often, or else just use BDU's. Lots of camouflage options out there, although I do prefer the half-ghillie.