Ubaldo's a truly stellar host, and the place is amazing, as well. When I was meeting him, I forgot our meeting point, and had to search around the station for WiFi (tip: there isn't any unless you register with a cell number). I eventually found him some 20 minutes after we were supposed to meet, and he was still waiting patiently!
As for the place itself, it's spacious and well-equipped, and it's quite nice to have the garden out back. It's away from the city center, which means it's away from the noises of tourists and street vendors, although it does mean it's a bit of a trek to most of Florence's attractions. There are buses that take you there, from what I've told, but honestly, it was close enough that I didn't use them.
Overall, I'd highly recommend both the place I stayed and Ubaldo as a host.