very Interesting.... a 2017, still new...
Either way when I compare my new 2020 to my older 2016, I am very pleased wit the newer unit.
I found that the fit and finish is about the same on both, just the 2020 has more whistles.
We particularly liked the floor plan of the 3991RD because it gave us opposing sofa beds , 1 for each daughter.
We usually have 6 of us when we do the beach and all 6 sleep comfortably ..
2020 3991RD with-
17.5 Goodyear 114's , Titan Disc brakes, MorRyde 8K IS, Onan 6.5..