We had a great stay at Julien and Myriam's appartement. The location is convenient (only a 15-20min walk to the historical center), the check-in and check-out process is fully automated, so you can arrive at anytime without the hosts needing to be present (make sure you have access to the Internet on your phone so you can proceed with checking in). We didn't really interact with the hosts, since they keep to themselves in their part of the appartement, but it's really easy to get in touch with them if there's any problem or question, by sending a message by text, email or through Airbnb private message, Julien is very reactive and quick to answer. The bathroom is shared, as stated. It's important to note that guests don't have access to a kitchen, only a small fridge with cool drinks and water, a coffee/tea maker and a few breakfast options available in the entrance hall (in exchange for a few euros). The room doesn't have any air conditioning, only a couple of fans, so the room stays very hot in the summer. The street on the side of the room can get a little noisy in the morning if you leave the window open.
All in all we really enjoyed our stay, a great price for a nice and convenient room to explore the wonders of Firenze!