We were a family of six (four small children) and spent a few days in the appartment. As far as size and conveniences are concerned, it had all we needed. The flat was very clean and spacious. We had individual beds for each, three bedrooms, living and dinning room. We had a complete set of excellent kitchen appliances and tableware and were able to have lunch and dinner in house.
The appartment is well located if you have a car since it is just outside the restricted area. At the same time this means it is not so centrally located. However, Florence is not so big and you can certainly walk from the appartmen to the main tourist attractions (we did). Otherwise you have good public transportation available.
Both Leonardo and his brother Steffano were excellent hosts and helped us with all we needed.
The only criticism I can make is that the central heating is rather sparingly supplied by the building. To compensate for this, all three bedrooms have air conditioning which can be used to add extra heating when needed.