Guess I'll throw my 2 cents into this ring. I have a 1995 Ford E350 7.3L Turbodiesel Ambulance, and I would 100% do it again.
(Don't mind the fact I only used two straps, I've wised up since that pic.
I bought it off craigslist for $2100. The guy originally wanted $3200 for it, but went and test drove it, waited a week, then told him I was broke and could only do $2100. He accepted the offer right away, which made me think I shoulda offered $1800.
It has 187,000 miles on it. Only thing that has gone wrong that wasn't due to negligence was that the glow plug relay was shot, so I had to replace that once temps started dropping below 50 degrees around here. We had a tire blow out on the rear, but that was primarily because one of my crew guys thought he'd get home quicker by doing 85-90mph for TWO HOURS on tires rated for 75mph while we were all asleep in the back..... on a 14 hour trip from MN to St. Louis....
It has fantastic room for storage. I can fit an entire transmission and a spare longblock in the side compartments. Electrical outlets everywhere. I have a minifridge that is plugged in for rally weekends, big lights on the side that can light up the service area, speakers throughout to blast tunes. Nice bright lights inside. I also have a couch setup in there, and for the really long trips I can put a TV and PS3 in there for entertainment.
I park it either at my house, or in a storage area a few minutes away for $20 a month. I do use it for Home Depot trips and for hauling big things. It can swallow a fridge and a couch no problem. Used it for moving all my stuff when I bought a house a few months ago. It drives really nicely around town, just feels like a van (since that is technically what it is) and people always seem to get out of my way quickly on the highway.
I get about 12-13mpg when towing on the interstate at 65-70mph, and when not towing I get 16-18 I believe. Haven't actually filled up the tank and drained it when unloaded, since it takes 35 gallons... It get's expensive quick.
Either way. People were telling me it wasn't going to be the best idea since it's rather large, and unconventional. But I wouldn't have it any other way. Far exceeds my requirements for a tow vehicle, rock solid reliable (did a 1600 mile trip to MN and back without a single hiccup besides the tire thing), and all for just about $2000. Can't beat that.