We have a Unity 24IB with the Mercedes diesel engine. The Unity is a delight but trying to get service while on the road has proved a nightmare. Our "check engine" light came on for no apparent reason and none of the local shops can diagnose the problem as Mercedes has not adopted the 1999 service standard protocols. Even worse the closest Mercedes Dealer in Traverse City, Mi. can't service theme either! I mean really!! We have to travel 5 hours, one way, out of our way to get this looked at. This lack of service availability has convinced me not to by another with Mercedes power until this is resolved.