I stayed at Chiara and Stefania's apartment, along with my parents and a friend of mine for 2 nights when we visited Florence and it was just perfect. The apartment is huge, with ample space for the 4 of us - 2 large bedrooms and 2 bathrooms. The house was super clean and the showers were lovely and hot (an important factor for us when travelling!). There was no wifi but that didn't bother us. The kitchen was really well stocked with everything we needed to make our breakfast and lunch.
The apartment is really well located close to the river and only 500m from the train station, and only a short walk to get into the centre of town. It is on the 4th floor (with a lift) and was super quiet. The balcony has a nice view across the rooftops and you can even see the top of the Duomo.
Chiara was really easy to communicate with and was really flexible with our arrival time. In fact, everything was faultless and I highly recommend staying here on your visit to beautiful Florence!