The apartment is perfectly located - Casa Bargello right around the corner, 3-4 minute walk from Duomo. It's really quiet at night and you can sleep peacefully (during the day we repeatedly heard a piano play form the apartment next door, but it was in fact nice because the pianist played really well).
Michele is a great host, always fast to respond and very helpful. Our flight was cancelled so we had to postpone check-in day and time and Michele was very understanding about it. He also offered us great advice on places to see and things to do in Florence.