Mario is an excellent host. We rented his space for a month for our parents to stay in around the time of the birth of our second child because it is close to our own apartment. (2 separate "shifts"). He was very accommodating, friendly and helpful.
I did not stay there myself, but both sets of parents reported being happy to stay there. It's quiet, since the room is in the back of the building away from the street, though you can feel the R train go by. Thankfully it's not one of the busier subway lines. :-)
Both sets of parents said they'd be happy to stay there again.