I recently bought a pristine ML 200mm/4.0 from eBay, for a very modest sum (~95USD), and it included all the original accessories, cards and box. I must say I'm pleasantly surprised. It is all-metal, very sturdily built, the focusing helicoid is just as smooth as a Zeiss'. It produced crisp and constrasty slides, although I noticed a teeny bit of pincushion. I do not own a Tele-Tessar 200/4.0, so I cannot compare them, but these lenses look very much like twins. The official specs seem very similar. Is it possible the only difference is with the coating (ML for Yashica and T* for Zeiss?) In any case, if you can find one at that price, I think it is a very great bargain. Also on the plus side, it has the same filter thread as many Zeiss lenses (55mm). Other Yashica lenses have a 52mm thread.
GC