We stayed at Ben's place for 7 nights. The biggest advantage of his place is definitely the location - young neighborhood, walkable distance to many cool bars and cafes. Closed to two metro lines, it was easy and convenient for us to get around Paris.
As for the apartment itself, it's a small studio apartment - simple bed, small shower, there's a small kitchen and nice balcony. The building has good security and we felt completely safe.
Ben is a welcoming host who cares about hospitality. We were two hours late to the scheduled check in but Ben was always available and stayed for us - much appreciated!
Ben's place is perfect for those who mostly cared about the location and less about the underlying apartment or the amenities.