I have this lens. It's my only manual focus lens. I absolutely love this lens. Stellar performer, at least my copy is. Your price is is insane. I bought mine for $100 but that included a certificate of a professional CLA that was just done like a month before I got it.
Definitely worth it for a good, better than 'good' manual focus lens. Particularly on FF it's now one of my favorite lenses.
Shot below was taken wide open with my copy of this lens on a K-1.
---------- Post added 08-17-18 at 01:24 AM ----------
No offense but you're crazy for selling this lens.