We've had good luck with Atwood appliances, rack-and-pinion slides, spring suspension and rubber roofs but roof coating is a good thing after about 8 years and some sort of upgraded equalizer has made an improvement to the springs. Even our first three lower level RVs had Atwood but the frames were under engineered and the flexing caused problems with the rest of the RV staying together. Used can be a VERY good thing cuz you have a better chance of finding a stacked boxed frame and the other bugs are worked out. Sunnybrook has a boxed frame and I think Carriage, Arctic Fox, Nuwa and a few others. Craig