What is nasty about a cassette that is not even nastier about a black tank?
You need to empty them frequently, but we use ours without chemicals or SOG fan. Nothing particularly nasty about them.
My personal experience with build quality is with a few other brands other than Northstar as well. Compared to the other campers I had and some I have seen up close, the Northstar is nicely built. A bit old-fashioned, that much is true. But it is not like aluminum framed campers or fiberglass shells are always problem-free. They all have their pros and cons. At least the Northstar people know what a drill is and how to use it, and how to measure a right angle... Yes, the quality bar in RV manufacturing sometimes really is that low.