Why do you say this? One of the attractions to the northstar is the build quality, everything I've seen says that it's very good.
We prefer cassette and aren't interested in changing to a composting.
I say this as an owner with a Northstar and cassette toilet. Calling the build quality "very good" in my opinion is pretty subjective and compared to what? It is a wood framed camper that will rot if the slightest bit of water gets inside. It still has the same old typical RV 'rubber' roof. They haven't changed the interiors in 20 years and arn't receptive to change in general. I called them one time about a question and an issue I was having, their response was that they had new campers rolling off the line in a month and should buy a new one. To be fair, the way I use my camper is probably designed beyond what it was engineered to do which is RV parks and very occasional use.
Have you used a cassette toilet? They work fine for a short weekend, but beyond that they are a major pain in the butt, not to mention how nasty they are.