Hotel or agriturismo?

Hotel: more impersonal, in town, poss. More flexible for a cancellation, poss breakfast only,
Agriturismo: outside of city center, quieter, more for your euro, option for guest to host interactions,
Parking, poss pool, poss all meal option., fewer guests, poss larger accomadations for similiar rates.

I prefer the authentic rural experience of an agriturismo. Virtually every farm south of Florence has apartments and rooms for a secondary source of income.

The only thing is that you've got to be willing to rent a car. It's the only way to really take in fabulous hill towns like San Gimignano, Certaldo and Volterra.

Where else will your host furnish you with their own wine and brown eggs from their chickens?

Hotel:
+better for in town/city experience, short stays (under 3 nights), for stay w/o rental car. Serviced daily.
-less bang for the money.
Agriturismo:
- No room service in many cases, except for a couple nights a week. Little interaction with locals since they are isolated. Many require a minimum number of nights. Car is necessary.
+ Much more space and amenities for the money. More relaxing. Better deal for longer stays and/or big groups.

Well, you can do both. You can have a hotel in at little town, or agriturismo very near a town. That is the best of both worlds. We have stayed in both situations and you get a real feel for Italian life. One we liked was Villa Arnilu where you can rent rooms by the day and it is very close to San Gimignano. Day trips to lots of places.

If you are looking at staying around Siena, check out Francis Lodge - it's up on the hill above town so you have the agriturismo/b&b but you are close enough so you can walk down to the city center in the evening to stroll. And you can view the town from their hill !

We stayed at the Agriturismo Marciano just outside Siena on our honeymoon a few years ago. I cannot compare it to other hotels in Siena since my only experience in that city is the agriturismo. However, I can compare it with other hotels in Italy. The agriturismo has MUCH more charm than the typical hotel. We were able to join our hosts for a freshly prepared feast one evening that was by far the highlight of our trip. Sitting down to a 5 course intimate home-cooked meal with all 6 of your fellow guests (and 9 bottles of the agriturismo's wine!) is something you would never find at a hotel. I understand there are exceptional hotels out there, but in my opinion, (and admittedly limited experience) you just cannot beat what the agriturismos offer.

Disclaimer my advice is based solely upon my one experience. I highly recommend Agriturismo Marciano!! Other agriturismos may be better or worse, but if you choose them I don't think you'll be disappointed.

Also, I almost forgot ... someone above me said you have to rent a car. Agriturismo Marciano is located outside of the city proper, but is certainly within walking distance. I believe it was a 15-20 min walk to get to the city center. And the agriturismo was still far enough out that you felt like you were in the country, not the city. I personally enjoyed the walk. As we went along, past stone walls and vineyards, I kept thinking about what the American soldiers thought in WWII as they walked along similar roads. It's silly and off topic, I know, but that's how my brain works and for me, it was a really cool moment.