We stayed in Alessandro's place for 2 nights. The location - just a few minutes' walk away from both the Duomo and Uffizi - was outstanding, although the 53 steps up to the apartment wouldn't be suitable for everyone.
On arrival Alessandro and his wife took us on a detailed tour of the house to show us how everything worked, and then suggested a whole load of places to eat meals and ice-cream, bars and the best ways to experience the city. On their advice we visited Fishing Lab, a modern fish restaurant around the corner which was a welcome change from all the meat we'd previously eaten in Italy! The food was superb and reasonably priced. The restaurant underneath the apartment was also very good. Finally do make a visit to Venchi, possibly the best Gelateria in Florence (and definitely the best recommendation they made!)
The apartment itself is beautifully refurbished and very stylish. There was everything we could possibly have needed, although we didn't cook anything so didn't really use the kitchen except for fridge storage and the coffee machine. Showers were hot and there was excellent water pressure. The aircon was a blessing after the hot late July days (38C) in the city, and the WiFi was handy for planning our days in Florence.
Finally, we really appreciated the bottle of chianti they left for our stay. We unfortunately didn't have time to drink it in Florence as it was only a short stay, but we took it with us to our next Airbnb apartment in Venice and drank it overlooking the gondolas on the canal outside our lounge window.
Overall, we would highly recommend CondottaSuite14 to our family and anyone visiting Florence.