We had mixed feelings about our stay here. Firstly, it was very difficult to find (it is on google maps twice in two different places, and their own website directed us to a layby). The road up to the hotel is a steep gravel track which our little Fiat 500 just about survived. We had booked a one bedroom apartment. On arrival, after walking round the building twice with the person showing us our room, we were shown to a cell sized room with bunk beds, before actually getting the room we booked after protesting (we couldn't find the hotel, she couldn't find the room!) The apartment itself was nice, with original features, but the kitchen facilities felt limited (we did not use these in the end as we only stayed one night).
We had originally planned to stay for 3 nights, but just stayed one night after a poor welcome, and as the location didn't suit us - it felt quite isolated, and we felt would be difficult to use as a base for accessing nearby Siena.
The castle itself is beautiful and the restaurant was amazing - traditional Tuscan food, but in a modern style - the gnocchi with pistachio pesto was to die for, and the peposo (stew) was divine.
The wine was lovely with the meal too, but it would've been good to have a wine tasting, but none were available until after we left.
All in all, would we stay here again? No. While it was perfectly nice (and in some ways fantastic), it is set up as a place you escape to, and we just wanted to escape from it.