I had a couple of tourers staying with me that like them a lot. They actually had them given to them as they were on an around the world ride for "charity".
They way I see it is they are pretty much bullet proof and rarely does something go wrong. The problem is when something does go wrong you are pretty much screwed.
A traditional derailleur while fragile can at least be rigged till you get to a bike shop for replacement. Try and find a Rohloff at a tiny bike shop in Podudunk, Iowa.