Our experience with Alessandro and the flat was excellent! Even though we weren't able to meet him in person because he was out of Rome, he was very helpful, answering immediately our every question and proposing places to go and see. He also made some arrangements with our check-out in order to help us with our flight schedule.
The flat itself is small, clean and cozy, with the basic ammenities and a traditional Italian feel. It's not the place i'd recommend if you plan on staying mostly inside but for someone moving around it's perfect. It's located in the center of Rome in a quiet little street and it's walking distance from every major sight. In 4 days we never had to take any transport and just walked around (which is the actual way to really experience Rome).
As a side note, someone with mobility problems may have a problem ascending the stairs both of the building and inside the apartment to get to the bed (although there is another couch/bed I'm pretty sure it's not as comfy) so keep that in mind.
Overall great host and exprerience!