Nanse, you are not the only one with that problem. I had a friend that was a trailer salesperson for many years, she also suggested to not buy a Sundowner during a certain time period because of the problems. The trailer didn't have to be uncared for to rot.
Just recently while shopping for trailers we came a cross a big fancy Sundowner stock trailer(show cattle) that had a sliding center cut gate, you could move it all the way to the front, use it for a studwall or feed room, move it way back too haul cattle and load a horse or two on the back. It had a 5 ft straight wall tack room....fancy, they about had us convinced we "needed" that trailer. We would of bought it if it have Sundowner written on the nose.
Every brand has their bads years, no different than trucks. At first Platinum Coaches were the greatest and nicely built. A friend who team ropes spend a pile of money for one and has had it in the shop on several occasions because it leaks.... you just have to pick through them I guess.
I DON'T LEAD 'EM AND FEED 'EM, I RIDE 'EM AND SLIDE 'EM.