Long post coming, but this is a pretty big investment ya might be making here. I have experience w/ a Sprinter, albeit a 2006 model. In most cases (other model vehicles) getting a slightly new one is a good idea. I would NOT do this w/ a Sprinter. Mine was nothing but problems. Also important, I worked w/ about 50 people who all had Sprinters in my previous job. Of those 50, I'd say 35 hated their vehicle, 10 were nuetral on it, & 5 really liked it. Two guys had repair bills in the thousands on vehicles that didn't have that many miles on it. Many of us, including me, had smaller but still frustrating problems. From mechanical problems to things like the fan didn't put out enough heat to defog the windshield. The problems varied, but there were many.
As for the UPS & Fed Ex guys driving em. Yea, they do. But also remember that those companies have fleet mechanics & if I'm not mistaken company trucks, so it's not the individual driver stuck w/ the repair bill.
Now, I'll concede that in the few years since all those lemons came out, that Sprinter quite possibly got their act together & made some improvements. No way could a vehicle be worse. So it's quite possible that most Sprinter owners are happy w/ their vehicles. I'm not sure as I don't keep in contact w/ my former co-workers. But whatever ya do, do NOT get a slightly used vehicle.
Another thing ya may want to do is go to ExpeditersOnline.com & ask questions of those people. A lot of people on that board have Sprinters I would imagine. You're going to have to make up a screen name & register, but it's pretty simple & free. For the investment you're thinking about, ya might get better information from which to make your decision. It could save you thousands or help ya find out that Sprinters are now a decent vehicle.
Good luck to ya & hope this helped.