I use my H3D seven days per week as my main camera, mostly on location (warm and dusty), and have done 27000 clicks in 9 months, without any major problems except some contact issues between lens and body that I have been able to solve on location. I trust my H3D enough these days that I don't carry a backup system anymore.
In the past 25 years I have used almost every film based medium format system there is (ETR, SQ, GS, M645, RZ, P645, P67, F645, F680, F617, Plaubel, 2000/200/500/SWC, Arca, C645, 6000, Noblex, L617) and have never had a system without problems of some sort. Obviously an advantage in the 'old' days was that you could fix many problems yourself with a coin (!) or a screwdriver/hammer. I don't see the H3D as any more 'fragile' than any other camera out there. Of course, could be I have been lucky.