So we have a 2016 4250HD and love it(who wouldn't ) its 43.6 feet of awesome
! So with that being said our only regret is we did not order the 3rd ac for the living area. I am happy to say we have had very few minor issues and the rest just comes with the territory.
Now for buying one used, this could have its benefits, for example, it may be clean on the inside. its amazing how dirty these things are from the factory. Another benefit may be all the adjustments have been made and little things tweaked, I talk about this because I myself probably have about 25 to 30 hours doing adjustments and tweaks.
Like mentioned by others its probably a good idea to find out why its used for only a year.
What ever you decide, good luck!
Happy Trails,
Mike