I spent five nights in Arianna's flat and was happy to have chosen this refuge over a hotel. The flat was very clean, carefully decorated, spacious, fully equipped, and exactly like on the pictures. It is located about a 5 min walk from Ponte Vecchio, but just outside the usual tourist circuit, and I really enjoyed wandering around and discovering the neighbourhood and a slightly more local feel to Florence. There are plenty of great restaurants and shops nearby. Arianna was very helpful and contactable throughout, and checking in went without any problems.
That said, be aware that the flat is on the ground floor and the bedroom is right on the street - perfectly quiet at night, but despite earplugs I did not manage to sleep once traffic started up in the morning. I chose to make the most of it, get out early and beat the crowds. Due to the thick stone walls, there is also no mobile reception anywhere in the flat, and the front door can be a bit tricky to navigate - I had to ask people to give me a hand with the key a few times. I would still recommend staying here though, especially if you're an early bird.