Sprinters
We currently operate several Sprinter boxes, but I've never used the van style. As far as our Sprinters, I have mixed feelings. They're smarter their drivers, using differential braking on hard curves, automatically applies brakes when it thinks you're overdoing it, etc., but the truck's definition of overdoing is considerable more conservative than mine. The visibility in the cab is phenomenal (large windshield, tall side windows, good sized mirrors), but it still seems to have a sizable blind spot and the size of the window makes it impossible to keep clean (scrub off the bugs and it's covered again after the next run). The cab also has numerous hidden storage spots, so stashing things like sun glasses and snacks is no problem. Each of our shifts has hijacked their own spot so we don't have to move stuff off after shift.
We've had some serious electrical funkiness with ours. The low voltage alarm is so sensitive that it goes off constantly, dash fuses seem to blow easily, and there is no light for the passenger side only (if I want to do paperwork on the ride home, my partner has to suffer the cab light as well). The brakes aren't very responsive unless you lay into them, then if you double tap them, they'll throw you into the windshield (those of us used to power brakes have to get over the habit of pumping very quickly).
My biggest overall complaint is the lack of power. Our's are the ~150 horsepower (I'm assuming 4 cylinder) engines. Our district is very large, with a lot of county highway and wide open country roads, but the unit is governed at 82 mph and it performs very poorly climbing mountains or even steep hills. It has a 5 speed slap-shift, so if you have to come to a stop at the bottom of a hill, you can manually downshift to first gear and climb it that way, but it's still a tough climb if you have no momentum going into it. Also, it doesn't get the fuel mileage one would expect from such a light duty vehicle. We average 15-20 mpg (my estimate, I haven't actually crunched the numbers), but my district's terrain might have something to do with that.
Overall, I've used significantly worse trucks, but I miss my light-to-medium duty Ford truck chassis. For a service which covers mostly urban terrain and has a lot of stop/go traffic, the Sprinter would be great, but for combination urban/rural, mostly rural, or mountainous districts, it just doesn't perform as well as I think it should.