I see your from MI so let me toss out A&S RV in Pontiac, MI and Kitsmiller RV in Mason, MI as 2 dealerships I have had very good experience with. American RV in Grand Rapids was very good 12 years back but have not had any recent experience.
You might want to make your question a little more specific as to area or region. (South west Mi, Upper Mi , etc)
You also might give more information like your looking for sales or service. Some places have great sales staff but can't fix anything. Others have good service but sales may be difficult to deal with. Only a select few are good at both ends of the building.
Randu