The apartment on Tornabuoni is excellent and in a great location. We were right in the center of the city with an easy walk to every major sight. The apartment was clean, modern and had all the required amenities. We stayed with an 8-month baby and it was very comfortable. Communication with Luca and Abla was excellent. They were always available and responsive, including at night post office hours. Luca’s recommendations on places to eat were also spot-on. Osteria San Spirito was excellent (try the Gnocchi, make a reservation before you go). As others have mentioned, there are a lot of stairs, but we knew that before we booked and it was not an issue for us.
I would have given 5 stars, but am giving 4 for two reasons: our baby cot was late to get to the apartment;
there is a requirement to throw out the trash (which we were totally fine with) but the trash receptacles are not in the building - they are a 5 min walk from the apartment and a bit inconvenient.