I've got a couple of XT6s, and neither have any rust problems. I'm in Washington State, and we don't put steel-remover on our roads during the winter. (We prefer paint remover instead.)
Can you tell I loath sand/gravel and salt?
The variable-assist power steering and air suspension tends to fail. The air suspension can be challenging to fix, but once you understand
exactly how it works it's quite possible, but can be expensive. I think the problem with the power steering is that the brushes for the electric motor wear out or fail. I don't recall exactly what the problem was, but I remember that it wasn't the end of the world and that it can be fixed properly so as to prevent it from recurring.
Aside from those two problems, they tend to be pretty good little cars. I'm looking at acquiring a third one.