It's all a matter of how it's been maintained. We bought a new FR Salem early this year and have been pleased so far. I think they are about average overall as far as build quality, but can vary from one to the next. Just inspect it thoroughly with particular emphasis on looking for any signs of leaks. I'd open every compartment and look around with a flashlight and even a mirror as necessary. There are usually at least a few panels that will require removing a few screws in order to open. On mine those include access to the water pump and the furnace. I'd also crawl around under it looking for any issues as well as carefully inspecting the roof. If the roof is in bad shape and looks like there are areas that may have allowed water to get in, I'd probably steer clear. But if it looks like overall it's been well cared for, I'd have no qualms about buying it.
Rob and Julie
2015 Forest River Wildwood 28DBUD
2001 Dodge Ram 2500, 24V Cummins 5.9