I have a 2009 Monaco Cayman and like it very much. I bought mine new and was aware of the trailing arm issue. I viewed it as a $5,000 problem... which is the approximate price of an installed Source Engineering trailing arm replacement and Ride Enhancement Kit. It took care of the issue and improved the ride substantially. This is my third motorhome and it rides better than any of my past coaches with the Source Engineering modifications. I am currently a full-timer and have driven the coach all over the U.S. with just short of 30,000 miles.
You'll find that ride quality is very subjective. If you have a Prevost, you won't like anything else. If you have a 10 bag chassis, you won't like the 8 bag.. etc. I know that mine doesn't ride as well as the more expensive Monacos... but it rides much better than any of my previous gas motorhomes. Also, my exhaust brakes work just fine. In fact, I recently went down Wolf Creek Pass in Colorado (which is very steep) and only hit my service brakes three times. Of course, this is just my opinion.
If you can get a great deal and are willing to budget the modification, I think it is a fine coach.
Ron Clanton
2009 Monaco Cayman 38PKQ
KE7NJ