We were a family of four travelling by car and stayed 3 nights during a very hot part of the summer. Martina's place is great. The location is UNBEATABLE. Right in the heart of the historic centre, a few minutes to the Duomo on one side and another few to the Palazzo Vecchio on the other. Lots of restaurants practically around the corner. A little hard to find at first but the entrance is literally across the street from the Amorino Gelateria (Just punch that into Google Maps and you're there.) There are a lot of stairs, but that is the price you pay to have a terrace with that spectacular view sipping Prosecco in the evening after a day of touring. The Air conditioning worked well and wifi was good. Very spacious and funky decor. Also provided a nice reference booklet with tips for where to eat. Martina was quick to respond to texts and her colleague Leonardo did a nice job orienting us at check in (even brought one of our bags up the stairs - nice guy).
We were able to drive to and park right in the historic centre at Garage Bargello. Pricey at about EUR 35 a day, but literally 2 blocks away, and worry free as they take care of the ZTL restriction. Worth it if you're only there for a few days. Highlights were the Florentine steak at il Tuscani 2, sandwiches at Al'Antico Vinaio, and gelato at La Strega Nocciola.