I had a great stay. Zein is a friendly, welcoming host. He was around the apartment here and there, but doesn't live there -- I believe he's in another apartment in the same building.
The room is much brighter and airier than the photos would indicate, and the little couch is a nice touch. There's a wall-mounted AC, but the massive screen window was usually sufficient in the evenings. The bathroom and kitchen are very clean and modern. Living room is on the smaller side and directly off the other rented rooms, so it doesn't serve as great communal space. That said, I can't imagine this is important to most people and the kitchen is more pleasant and has seating as well.
Street noise is very minimal, limited to only the passing tram (and its occasional chimes) a half-block away. The tram also means that getting there from the airport or train station is a breeze, although the latter is walking distance. Central Florence is an easy 10 minute walk away. Should you be attending a conference at the Fortezza da Basso, as I was, it's less than 5 minutes if you go along the main road passing under a tunnel (mapping apps will direct you on a 15-minute loop).
Note that the private bathroom is not attached to the bedroom, but is directly across the hall. The WiFi also was out for the first couple days, but it appeared to be due to some ongoing construction outside Zein's control. I'd have appreciated a heads-up, but what can you do.