Marco was the best host I have ever met on AirBnb : he came to welcome us at the vaporetto station, he helped me with my luggage, he showed us around the appartment, we got a bottle of champagne as a gift, and he even came back on our request because we had some trouble with the wi-fi.
Regarding the appartment itself, it was well situated, in a nice neighborhood, central, not noisy... The ceiling is pretty high which makes it very nice to look at and there is a lot of space. The bed was a bit hard but I have seen this remark on many reviews about italian appartments, therefore I guess that is a cultural difference.
One tip : bring slippers if you come during winter because the floor (tile) is a bit cold !