We too have had excellent support from Newmar. In fact, rather than go to a local dealer, we just returned from a trip that included a stop at the Newmar facility in Napannee, IN. Like Tiffin they have full hookup sites for you while you are being serviced, and they exceeded all of my expectations while there. I to think the Dutch Star is a higher grade coach than the Phaeton, but both are nice motorhomes. Having been an engineer in a previous life, when I get "into" the motorhome, I am VERY impressed with the engineering of our Newmar, which is the lowest cost diesel that Newmar makes. It has some features that our previous Revolution LE didn't have.
If I were in your shoes, I would probably get the motorhome that has the floorplan and amenities in it that you like the best. You can't really go wrong with either manufacturer.
Ed Headington