What you're mostly gonna get on MOC is how much they love their Montana. Nothing wrong with that as they wouldn't own one if they didn't like them.
I recently traded in a HC 343RL and could give you some insight.
We loved the layout and build quality for the most part was no better or worse than comparable fifth wheels.
Keystone during the warranty period was great to work with.
Front cap and decals faded/peeled. I saw (MOC members) that Keystone was covering the decals after warranty but they wouldn't in my case.
Largest reason I traded the trailer was that it only had 5200 lb axles on it. On the surface with a 12,500 GVWR it would have been ok but the layout of the trailer with 3 slides, kitchen, water heater, bathroom all on the left side... The left side of the trailer was overloaded. The left springs flattened out after a year where I replaced them with heavier springs but they flattened out as well. The trailer had a noticeable lean to it when on level ground.