Got it, Thx Fen. Sorry I got this thread off track a bit regarding how to use the app, rather than which hardware works best with it, which was the OP's initial question. Seems like the consensus here is that a gps is a "feel-good" device that's primarily used by most as a back up, and that some guys have given up on packing one at all, relying instead on just their smartphones. So now I guess have to decide if buying a gps that is On X compatible is worth it, just to prove to myself that I don't really need it...