Motorhome depreciation and selling question.

Currently looking at a motorhome purchase and have spent ages on the Internet and visiting dealers sussing out the pros and cons of various layouts and new verses used.

My initial reaction at prices dealers seem to be asking is that the initial depreciation does not seem to be as bad as that found with a car - as in it seems more sensible to stretch yourself to a new rather than used model of around 2 or 3 years old as to buy used you don't seem to be saving that much.

Is my impression correct? or am I looking at dealers who are overpricing their used models?

Also a couple of MH's we have looked at in dealers are 'being sold on behalf of a customer' obviously they will get a fee out of doing this but are there any pitfalls from making a MH purchase in this way?

Thankyou..