We love our Heartland North Trail, we bought our pre-owned unit early last year.
I'm guessing the previous owner did not winterize it, so we had an issue with the shower diverter early on.
Also there was an issue with wheel alignment that was causing some abnormal tire wear. And another North Trail owner recently confirmed he had a similar problem. So keep an eye out for inner or outer edges of the tires wearing, and take it to a big-rig alignment shop if it needs work.
Finally I found out the hard way the previous owner had hit a tree branch and we had some leaking up at the front cap. A tube of self-leveling Dicor stopped that issue. So get on your roof early on and inspect all caulked seams.
We've been very happy with the build quality and features. I hope you have lots of fun with yours.