We chose this B&B as we arrived with a car and it was possible to park outside on the street. It costs 12 EUR per day (you can pay for three days infront), and its only meters away from the inner ring (just beware, they clean roads once per week, and for that night you have to move the car!). Location of the B&B is OK. Its located in "residential" zone of Florence and not in the tourist centre. It took us around 15 minutes of pleasant walk to the main attractions (a bit more to the river), and the walk is flat (unlike on the hilly south side of Florence). City market is quite close, and there are also several nice restaurants around there. If you arrive by a train, its around 30 minutes walk to the B&B, but you can also take a local bus.
Rooms... Simone doesn't have plenty of rooms in his B&B, and the whole place feels like a huge artistic appartment (upstairs is another great appartment for more people - including kitchen, nice terrace,...). We stayed in one the two rooms on the "base" floor which included bathrooms. Good size, clean. I didn't get bothered by the traffic. All the rooms are interestingly decorated, with unique paintings. Well... the whole place is interestingly decorated and it feels like an art gallery.
Simone offers good advice and tips on the Florence. He also can speak English if you need ;-) Breakfast is basic, coffee/tea/milk with fresh croissants. Wifi and a computer with internet connection are also available!
Bottom line. If you arrive with your own car (or without) and still want to stay somewhere comfortable, good value and close to the centre, this is the place!