RonR, Your experience is not rare. The MB engine can be a reliable and durable engine. However, the electronics that control it are so over-engineered/poorly programed that a very minor issue can render the Sprinter inoperable. I had a dead battery set a code that told the ECU the tranny was bad. I was left with reverse and 2nd gear. I could see the code, but only an MB device with proper software can reset it. MB won't sell you one. If you have a problem on Friday evening/Saturday morning any road service you may have is useless until Monday. Service and parts are expensive. For many such issues are an acceptable tradeoff for a compact/fuel efficient and maneuverable Class C or B that doesn't really require a toad.
The Sprinter is a superb vehicle for folks like FedEx and local service fleets. The key word is local. They either have in-house or local maintenance available. A Sprinter based RV on highway 150 in Nevade, or in BC, or in Alaska is a different risk. I won't risk a trip to Alaska in mine. Mostly we see the horror stories, like yours. My personal belief is that having paid the substantial premium for a Sprinter based RV, most users turn a blind eye to the occasional issue and we largely hear from the relatively few (the number of RV's on Sprinter chassis is really a very small number of the total population)folks who have multiple issues. I liken it to the African Bontebok. Every night a few of them get eaten - but there are literally millions of them. Not a big problem unless you're the one that's supper!
Similar situation exists with the Ford V-10. Since 1997, a couple of them "spit a plug" every day - with 500 to over 100 miles on the clock (mine had 127k). But, there are millions of them on the road. The problem never makes news, but Google knows it's there!
Wes
"A beach house isn't just real estate. It's a state of mind." Pole Sitter in Douglas Adams MOSTLY HARMLESS