The price range part of your question is tricky, a bit like "how long is a piece of string". It depends on the camper body, how it's made, how good it is, how well kitted out it is. Prices will probably range between $25,000 and $200,000 "depending". take a long search on
www.mobile.de to see some prices of all sorts of conversions (and not converted yet).
Concerns - not sure what you mean? That specific model year? camper conversions?.... Take a read through the unimog section on the benzworld forums, you'll learn more than you ever wanted to know about unimogs!
I've been living in a 1986 U1300L camper for almost 2 years, not too concerned about any of it. It just works. When something breaks, or needs servicing, I figure out how to get it sorted. and have never failed to get it sorted. not too concerning.
what are you specifically interested in?
Merv.