Marcello's unit is very tastefully furnished, extremely clean, spacious and comfortable. It was perhaps the best Airbnb unit in our price range that we'd stayed it. The unit has a lot of amenities such as espresso makers (with coffee pods provided!), nice functioning fridge and washer, He was very responsive and answered any questions we had promptly.
The building is older and does not match the interior of the unit (ie: old stairwell, etc...). It is in what looks like a a working class neighborhood. The neighbors seem friendly. Our 12 year old son had fun playing soccer with a kid in the neighborhood.
It takes about 40min to walk to the Duomo. The walk, for the most part is along Buenos Aires street which is lined with shops and stores. You can also take the subway, but it'd take at least 10-15min walk to a subway station. The apartments are on top of a row of Indian restaurants. We had dinner at the one directly below the unit and it was delicious. There's also a pastry shop Il Fornaio couple minutes away and groceries store PAM 10min walk.
Unfortunately, during our stay, the building next door was going through renovation and there were banging and jackhammer noises that starts at 8am and one night goes until 11pm. It was not Marcello's fault, but affected that quality of our visit. With that said, the unit was very nice and as mentioned we enjoyed the comforts and little touches Marcello put into the place to make it extra comfortable for his guests.