My 2 cents for what it's worth.
After sale service is strictly a function of the dealer and their customer service policy, this includes going to bat for you with Keystone.
I would say my experience with our 2020 is as good as it gets, took it back twice (in the first year), once for a leaking jack (ordered and couldn't get one because of stock so they took one off the shelf), and a broken TV cable connector on the set, as is normal I was upset when they said it was not covered longer than 90 days (it was my fault it went longer than 90 days, I knew about it in 10 days), but after I read through all the warranty information they were correct. The dealer offered to install the new 4K set I was going to buy if I brought it in but I did that myself.
I have talked to lots of Montana owners as well as SOB owners while traveling and the vast majority are extremely happy with what they bought and most are not so happy with dealer service.
Keep in mind this is a home on wheels and stuff (not the word I was going to use) is going to break, especially if you do allot of boondocking, off road or travel through Shreveport, LA on I20.
2020 Montana 3561 Legacy, everything except paint.
2018 Silverado 3500 DRW, 50Gal Transfer Flow, Andersen hitch.