I literally fell in love at first sight with this apartment - it is incredibly wonderful! The photos do not reflect how lovely, cozy and beautiful it is! Some moments that I would like to outline:
1) the IDEAL location, just IDEAL! it's very close to both main central bridges - St. Trinita and Ponte Vecchio, and though the zone is very touristic, it's very quiet! The supermarket Conad is just 3 minutes walk, a cafe is just the next door, on the same street there are lots of restaurants within 3-5 minutes walk. The containers for rubbish is 50 meters away.
2) the apartment itself contains effectively 3 floors: 1 - kitchen + dining room + bathroom/WC, 2 - bedroom, 3 - TERRACE! There's a fire-place on the first floor which makes this place very cozy. The terrace deserves some special words: the view is just spectacular! it's really 360 degrees, you can see the entire city of Florence with all its architecture! the sunrises and sunsets are extremely picturesque! It is ideal place for single travelers or a couple.
3) Federico is one of the nicest hosts I've ever met. Very responsive and helpful, he immediately answered all my messages and questions, gave me detailed instructions how to get to the apartment, met me personally and explained everything, including nearest restaurants, bars, cafes, places to visit and other useful recommendations. I was impressed.
This trip to Florence was amazing - mostly thanks to Federico and his apartment. I would love to come back!

P.S. I should be noted - sometimes it's important - Federico's apartment is on the last floor, and there is no elevator, and the stairs is rather steep. Besides, there are steps within the apartment, so the guests should be careful and note this before booking.