Personally I say go with suspension. With suspension lift you will actually gain wheel travel, ground clearance, and ride height.
Body lifts do nothing but gain creance for larger tires, IMO. They will stretch wires, steering linkage, and hoses. They will leave 3" gaps between the body and frame, male the motor 3"s lower in the engine bay (pain to work on) and the bumpers will either be 3"s too low, or raised with brackets that make them good for nothing but looks in an accident.
But I have heard on 98+ trucks they are the only option for some that cant drop 1500 on a lift. I have heard the kits now come with extentions for damn near everyting as well.