We spent two nights at the Hotel Athena in Siena during the month of January. It was off-season, so the hotel was not very busy and our room rate was very reasonable. We had an amazing view (we were on our honeymoon, so I believe that helped) and the most spacious room of all the hotels we have stayed in thus far (Rome, Florence). The location was less than a 10-minute walk from the city center (Il Canto) and even closer to the city's Duomo.
The hotel's customer service was knowledgable, friendly and representatives spoke very good English. We were given great recommendations for restaurants and provided with maps and taxis at the drop of a hat.
My only negative about the Hotel Athena was late-evening and early-morning noise. We stayed in room 708 and would typically retired at 11pm and awake around 7am. Both nights and mornings we heard doors shutting, people walking around and occasional conversations, which made falling asleep and waking up a challenge. We do not believe the rooms on either side of us were reserved, so the noise may have been coming from the room(s) above or across from us. This is not a noisy hotel at all, nor does it seem to have thin walls. So my husband and I were a little befuddled by who was moving around so much, particularly at 11pm and 7am. At any rate, if you are a light sleeper, I recommend requesting a room as far away from others as possible.