Both times I rented through a dealership that had a rental division, I wanted a late model diesel pusher, not the beat down Cruise America cabover style. Both experiences were great, with nearly new RVs that were in fantastic condition (downside is it's very evident if you damage it). One of the highlights of the trips for me is handing the keys back to the agency and walking away.
My recollection is that it worked out to about $500 a night with all the add on fees, but for a family of 6 that wasn't bad. We would have needed at least a couple of hotel rooms each night and we wouldn't have had the fun of the RV experience, plus we were able to eat breakfast and lunch on the cheap in the RV and then go to nice dinners in the city we were in (as long as I could park it). For a short vacation it's not a big deal to not have a smaller car to get around to things, but I can see why many people tow behind them a smaller car. We got pretty adept at hooking up and unhooking at RV parks, and made sure we planned ahead for picking up groceries when we could. At every site we visited there was ample RV parking.
Now there's a Turo like site for RV shares, those didn't exist when we rented.