Good luck on everything from build quality to price.
I have a 2011 Outback 298re. 36’long. I think it was reasonably well built if you don’t use it too much. My wife and I spend a few months a year in ours, probably 100,000 miles on it. The first thing on any of them is check the tires. Manufacturers seem to like to put the tire that is just barely enough to carry the prescribed load. Ours only has a payload of about 1900lbs so we probably overloaded it from time to time. 90 gal of waste water is heavy. Look at the A frame every once in a while. Ours broke and was on the verge of catastrophic failure. The repair shop was agast at how light weight the components were. Even so, I think it’s probably built as well as any of them, just always keep an eye on the running gear. Be prepared to work on it frequently. They do take a beating on the highway.
Enjoy. Shopping is so much fun!!!