We've actually driven past it since the Via Volterrrana road passes right by the front entrance and it is a beautiful castle But no, haven't stayed there or heard anything in particular about people who have stayed there. It seems to be a luxury estate, everything has been turned into apartments and there are like 30 of them! There doesn't seem to be any connection to agricultural production of grapes/wine or oil, at least not from their website.
If you'd like that as part of your stay, then I'd suggest staying at other estates nearby.
You should read my article on Montespertoli to get an idea of what the area is like ;-)