Hello Jim,
I have a Garmin rino 530. Gosh the thing will do about everything up to washing your back in a cool mountain stream....but there in just might lie the problem for me. Being half simple, err,,,the politcally correct term I understand to be "technologically challenged", it's not an easy unit to operate. It just does so many different things that my simple mind forgets how to operate it.
I bought an aftermarket instructional DVD and put forth some effort toward improving my learning curve but admittedly I'm not too confident yet. That Cammenga Compass and Topo map I still carry is very reassuring....
Specifically I have not had the ability to use the peer to peer feature, although I will be giving that feature a try out in 3 weeks during an Idaho elk hunt. A buddy has recently bought one so we can play with it together now. It doesn't work real well unless you know somebody who's got another rino to play with you.....
Looks to be a fine unit though and many accesories are available through @bay. I believe once a guy masters the operation technique it could be the cutting edge navigation equipt.