I've owned 2 Keystone trailers (2008 Springdale and 2015 Bullet Premier) and haven't really had any issues. I ended up with a leak in my old one, but that was due to my lack of maintenance....lesson learned. The new one we've had a year so far and we haven't had one issue yet (knock on wood).
There are definitely some small tings that I shake my head at due to crappy installation/construction/materials, but that's going to happen in almost any RV at any price point.
Overall, I think the trailers I've owned have been a good bang for the buck and we absolutely love our new Keystone trailer.