Does your friend with the Deus have severe shoulder issues or is he just used to swinging with a harness? I ask because I like the Deus as a no fuss, no muss minimal setup detector I can just grab out of the back of the vehicle and hit the site with minimal hassle. I have never thought of donning a harness with it as I am able to swing it all day and certainly for a few hours at a time and I am by no means a picture of orthopedic health lol. On the other hand, no sense in trying to be a hero out there if you have a bum shoulder or if you already have the harness strapped on to accommodate another detector, I suppose.