Get the cheap one. They are really sharp and contrasty. They do feel like a handful of plastic, straight from a Cracker Jacks box, but they work reall well. from my experience the regular 80mm is very close in performance to the Zeiss Contax 80mm. Other good "non-D" lenses: the 55 is one of my favorite lenses on any system; the 45mm is really, really great once stopped down to 8, even better at 11; the 150 3.5 is very good, not as good as the 80 and 55, but good. A little long for digital. The 120 Macro is one of teh best of the bunch.
The old lenses are great and a bargain. The Schneider lens, D variants etc, while better in absolute and relative terms, are not worth the premium over the old lenses unless you have the kind of revenue stream that can support it. The one complaint I have is that you can't manually focus the lenses without switching the body to manual, or in the case of teh 150, slipping the colar back. This always bothered me and I manual focused as a result.