Ciao Creasy Bear,
I've personally visited Villa il Poggiale for a dinner and a musical event, not actually stayed overnight. But I was able to see the gardens, the common areas and got a peek into the wellness area and everything I saw impressed me as being very elegant and stately, as it was a home in the past for a noble family. The welcome from all of the staff was very warm and even if I wasn't a guest, it certainly made me think it would be a good place to stay at. The dinner was really good, so I imagine breakfast and everything they offer should be high quality.
Sting's villa is called Tenuta il Palagio and is near Figline Valdarno, along the eastern edge of Chianti. It is practically due east from Villa il Poggiale. The estate's major business is wine, oil and honey production with a shop where you can buy all their products, including fresh produce, and I believe you can do tastings there.
If you take the fast route heading first to Florence and then on the A1, the trip takes about 40 minutes.... but if you take the scenic route through Chianti, passing through Strada in Chianti, the trip only takes about 10 minutes more (or more since you'll want to stop and take pics along the way) and will be more beautiful!
Here's the contact info for the Tenuta il Palagio Farm Shop
Via Sant Andrea 11, Figline Valdarno
and the coordinates for your GPS:
N 43 36.943
E 11 26.155
and the official site.