The major question about service departments on most of the RVs, big or small, driven or pulled, Winne or not, is are you going to get it fixed correctly? All of the service departments I have dealt with have been a problem, except for one and the factory. I have been down right lied to about repairs being completed. In my opinion, make your best deal and then RUN. Don't expect good service but do insist that the problem be fixed in a timely manner. Once the rig is in the shop call and visit often. Sometimes getting to know the personal in a positive light helps to put a 'care factor' into the work.
Happy trails,
Rick