Visited this Osteria three times whilst we stayed for a week at the Relais Del Lago, just down the road. Unfortunately we were there when it was a bit wet so couldn't take full advantage of the terrace - thus included a full on thunderstirm and a mass evacution to the inside. Nonetheless the inside is very cosy and quaint, and can accommodate quite a number, but would suggest it best to book in advance.
Food is typically Tuscan, very simple but very tasty with a good choice on the menu. The house red is very acceptable and cheap at €2 a glass.
The staff are very helpful and friendly with very efficient service.
Well worth the effort to find if staying a little further afield and thoroughly recommended.