I did actually try to contact Doktor A since I was going to be passing by him on my trip. No word back from him. (Was the holidays though)
From all the reading I've done, these vans can be plenty reliable. Lots of them out there in the 500-750k mile range. They have some failure points, common issues, and quirks just like any vehicle. Parts are on par with most things German.
I mean no offense here to any of the Sprinter owners. My observation has been that "many" (read as "not all", or not even "most") Sprinter owners use these for commercial use and their previous vehicles were domestic USA. So there is some diagnostic and sticker shock adjustment that needs to happen. Having to learn canbus systems and finicky German parameters, etc.
I have owned, ( and currently own 6) German vehicles. They are MUCH tighter on their CEL specs than say USA manufactures, and use it for far more things! Any hint of issues and it throws a CEL, unlike the USA made a stuff that seems to think the CEL shouldn't go off until complete failure of a part, or not at all for certain parts.
A great example of this is O2 sensors. I've had to replace them due to CEL on several of my German cars but never on an American made car. Yet when I did take out the O2 sensor on some of my American cars, it was proven to be bad. Often times they are the same manufacture too!
So the difference in "reliability" is often in the "perception" of repairs. Have to replace a failing O2 sensor or drive for 50k miles with a bad one and consume more fuel/poor performance/etc?!