Would anyone like to share their thoughts and experiences regarding Contax SLR's? I have seen prices drop on used Contax gear and it seems tempting to get an RTS to have access to 35mm Zeiss lenses. Any particular models to look for or avoid? I have been looking at the RTS, however, I noticed there are several more models on the used market like the 137, 159, 167, RX, AX, RTSII, RTSIII, S2, ST, etc. Any major differences? Any one more reliable or built better than another? Is the build quality comparable to the Nikon F series?