It was a pleasure staying at the Smallest Hostel in Florence. It was just as described. The place is located in the heart of the city, very well furnished and maintained. It is very conveniently located, indeed just 3 minutes from the Duomo and the Mercato Centrale. The Basilica di San Lorenzo is right next to it. Check-in was hassle free as the instruction was very clear. The building is quiet, but the outside noise can be heard clearly though, especially when market vendors move their stalls in the morning and evening, but the bed is so comfortable that the noise did not really bothered me.
I strongly recommend this place to anyone looking for convenience and comfort in Florence.