I have mixed emotions on the two. First, I don't know if you're comparing apples to apples. The Dutch Star is the equivalent to the Allegro Bus, not the Phaeton.
"Mr.Mark" brought up a good point regarding a chassis shop near you as being an important factor.
I have a new Newmar 4018. I'm a DIY guy and prefer never to take it back to the dealer. Since our purchase in January, it had a bad dash blower fan (was bad at delivery) was missing two screw caps, the front door MCD shade was not wide enough (in my opinion) and I had a check engine light twice and a noisy front door.
The dealer knew I wanted to do my own repairs and handed me a new blower fan. I called Newmar direct and told them I didn't like the width of the standard front door MCD shade and I was missing two screw caps. They mailed me both.
The check engine light was a Cummins issue with the EGR. They replaced it and I haven't had an issue since. The front door took some adjusting before I got it quiet.
We bought our Newmar off the lot and the only thing we didn't care for was the booth dinette. At purchase, we thought we would try it and see if we could get use to it. We didn't. We called Newmar and they built us the optional buffet and table set up. I went through my dealer for a big reduction in price and they shipped the new set up to my home.
Newmar is great to work with and after reading through the forums, I don't see a lot of people having warranty issues and is why you're not reading much about it.
We just looked at the 2015 Allegro Bus at the FMCA rally. It was a nice coach, but I personally have issues with either the Phaeton or Allegro Bus in a 40' length on a single axle.
Lastly, my tag axle and Comfort Steer drive like a dream. Many dealers will downplay the Comfort Steer because the can't offer it. We've been in 25 - 40 mph side winds (living out west) and you don't even know they're there.
PM me if you want to ask questions about the 4018.