We've been fortunate ourselves with our last 2 rigs in that we never had to bring them back to the dealer for any repairs whether in warranty or beyond. We did have some minor issues with interior trim where the dealer just gave us the parts we needed to fix it ourselves.
We do all our own upkeep and maintenance as well, on our current 11 year old TT all systems and appliances are still working fine with the exception of our convection microwave that we had to replace after 8 years. It helps to be handy, we done lots of mods to improve our RVing experience.