Personally, I wouldn't use anything BUT roof racks for bicycles (I have a set of load bars that is at least 15 years old). The hitch mounts show some promise, but I have seen too many bikes on hitch mounts banging into stuff. I am sure the higher quality ones don't do that, but still.

My roof mounted rack doubles as a ski rack and potentially a surfboard rack and "extra storage space" rack.

Delta, I am not an expert, but I think they make racks that fit into the beds of pickup trucks so the bike still rides in back, but it's secure to the bed. That's a great solution - out of the wind and rocks and not getting bounced around behind the vehicle.