There isn't really any one year that is better than another. If you buy a vintage unit you will come out money ahead on the front end, but will more than likely have to undo several years of neglect or PO damage. I have pretty well dissasembled my 1975, I am constantly finding little items that obviously were done by the factory that they are still doing today. Things like pop rivet pins and trash inside the walls, missed rivet holes in the skins, and things being installed out of kilter. Just decide what you year and model you want, decide how much you are willing to pay and go find the best you can for your money.
and be prepared to pay for the consequences.
They all (years and models) have their upsides and downsides.