My hunting partner and I both have the Rino 120s and they work really good for our purposes. The radio range isn't great, but they will give about 3 kms over mixed terrain, or up to about 5 kms or so on flat, open ground.
The peer-to-peer positioning feature is pretty slick. Basically your partner(s) position will show up on your GPS screen. The range for this feature is similar to the radio range. It works good if you split up from your partner and want to know or go to his position.
The navigation features are pretty standard as far as GPS units go. The 500 series of Rinos apparently have quite a bit better radio / peer positioning range, and might be worth a look.