I loved staying at Salvatore's place. The room was clean, bright, comfortable and spacious and the location was perfect. It was so easy to settle in and feel at home. There is some street noise but I knew this beforehand and slept through most of it, for lighter sleepers ear plugs would be fine.
The apartment is five minutes (literally) from the train station but also easy walking distance to pretty much anything else you want to see.
Salvatore is a great host (as an added bonus he has a beautiful - but shy - cat) and I highly recommend his place as somewhere to stay while in Florence. I certainly plan to stay there again in the future, when I return to Florence.