We loved staying at Andrea and Martina's studio. Andrea got in touch early and we coordinated our check-in time. He helped us with the luggage to the first floor where the apartment is. He gave us a tour of the apartment, and also told us about a nice cafe in the library building! The place was neat, and the kitchen had all the basic things in stock. The bed was comfy, and the street is quiet at night.
The location is great, with the Duomo just 5mins away. So you are close to the main attractions but not in the middle of the crowd. The Accademia is right opposite the studio, and you can just hop into the queue at around 830 am, before it gets too long.