We had an 05 Monaco Diplomat and loved it. We now have a 2014 Newmar Dutch Star and love it. Having had both, here is my opinion. I don't think you can go wrong buying a Monaco up to 2007 and look closely at any of the 2008 models (bankruptcy year). After that, I wouldn't touch a Monaco until they were taken over by Navistar. Even then, I would not personally be interested in one with a Navistar diesel.
For me, the Newmars have always been nice coaches, but the bland interiors never did it for us until I believe 2012 when they spiced them up.
Don & Mary
2019 Newmar Dutch Star 4018 - All Electric
2019 Ford Raptor Crew Cab