We stayed at Ciao Hostel for 2 nights and I can say the location of this place is wonderful. You'll be within a walking distance of the main train station of Florence and from this hostel you can make all your walking tours without any trouble. The street of the hostel is almost always full of cars (seems like it's a conection road from the suburbs to the center of Florence), so you will have to take care when crossing this street.
The staff of the hostel was always very friendly and helpfull for us, and we had no trouble at all with cheking in.
You have to keep in mind that the hostel has only one tiny elevator, but it's not always busy, so the stairs (which are large with confortable steps) can be an inconvenience to some people.
The room in wich we stayed was for 4 people, and it was very large and clean. The beds were very confortable. As we were in a room that was facing the street it was a little noisy (and add to that the fact that some guys who stayed in the upper floor got there at 3am one day and started partying), but the windows worked out pretty well when it came to block the sound of the cars.
There were two full bathrooms in the floor we stayed, but one of them had a damaged locker, so if one of us was going to use it, someone else would stay at guarding position. The bathrooms were always kept clean.
The wi-fi worked pretty well in the room (i'm not sure, but i think we were in the second floor).
The hostel has NO breakfast included.
I think this was a great place, and we would definately stay there again if ever we go to Florence.