We chose Palazzo Ravizza because it is located within the city walls of Siena and has secure parking (we purchased a new car in Germany and drove to Italy so this was a high priority). We stayed in the tower room with beautiful views of the hotel's garden and the Tuscan countryside, as well as great sunsets.
When we arrived early, the receptionist warmly welcomed us and stored our luggage while we went out to explore the town. It was about a 10 minute walk to the spectacular Duomo and about 15 minutes to Il Campo or medieval public square.
We highly recommend Palazzo Ravizza.