I'm sure there are plenty of houses within the city of Florence, but I am also sure that none will come close to the hospitality of Costanza and Desiree. They've been just amazing throughout the trip. Giving us hints on where to eat, what to see, where to go, what not to miss etc. The house is a particularity of the area so be open to trying something new, you will fall in love :)
Located near to the Palace, the Museum, the Train Station... you will not regret staying here at all as everything is literally a walking distance.