We really enjoyed staying at this apartment. The location in the Santo Spirito neighborhood was far enough away from the touristy downtown to feel relaxed, but close enough that you can still walk to all the sights.
The apartment itself is quite spacious and very stylish. The kitchen is very functional, we ended up cooking half of our meals at home. There is a laundry machine and dishwasher in the kitchen. Unlike other places we have stayed in Tuscany, the tap water was highly chlorinated. Not a big deal- just make plans to purchase your drinking water in a local shop.
The apartment was remarkably quiet for its location. Expect some street noise from the nightlife (especially on weekends) and some light noise from the neighbors, but overall it was very quiet during our week.
One note: for a great bottiglia di vino, stop by Enoteca Millesimi, on the same street! They have a really amazing selection of Italian and French wines. There is also a great restaurant (Tameró) located close by.