It was a pleasant trip to Boston, and the special extra credit should go to Mario. When planning for the trip, we were looking for a place that had three individual bedrooms. At this price, Mario's house was one of our only options. We did not have much experience with Airbnb and did not expect anything more than a place to stay overnight. When we finally arrived at this lovely three-story house after a long day of traveling, "Oh home sweet home!" was the only sentence in our heads. The private living room, dining room, and full kitchen were on the second floor. We enjoyed the comfortable couch, the large dining table, and the more-than-enough coffee, tea, and bottled water. Three bedrooms and a bathroom were on the third floor. The beds (a king-size, a queen-size, and a full-size in each room separately) were comfortable, and the rooms were clean and well-decorated.
Mario was a great host. He was very responsive and provided us with all the information we needed. He was also flexible about check-in time and parking location. More importantly (to us), the house was indeed an "[e]ntire rental unit" as described, and we enjoyed the privacy during the three days of staying.
The location of the house was better than we imagined. It was easy to drive around the area (location-wise), although the DT Boston traffic was terrible (a tiny better than NYC, and a little worse than DTLA). The public transportation seemed convenient, but we did not use any metro services, so we could not fully comment on that.
In sum, we stronly recommend Mario's place.