As you can see in our signature we have a Mountaineer by Montana. We have used ours extensively for the past two years. There were no warranty issues with the coach, but we did have to have the recliner mechanism replaced on one of our recliners as it was a bit one sided. I took the recliner to the dealer and he ordered the part and had it back to me in 48 hours.
At the end of this last camping season the Airconditioner quit cooling. It was covered by the Duotherm 3 year warranty. It turns out that the folks at Duotherm had placed a copper line where it would rub against the compressor and it rubbed a hole in the line. A local RV company did the repair ( 2 miles from home)and I now have a new 3 year warrranty on the airconditioner.
Neither of these issues were caused by Keystone/Montana but by their suppliers and both were taken care of expeditiously. So would we buy another Montana? You bet. We're looking for a 5th wheel as we are planning to go fulltime and will buy a Montana if we can find the right deal. Yes, we're happy campers and all of our friends love our coach too.
