I enjoyed very much staying at Mario's apartment. The place is just as described. It's in a calm street, 15min to the biennal or to St. Marco Plaza. Mario responded quickly to our messages.
The place is clean and have all the amenities described except for the wifi. It was a total flop. We couldn't even check our email, it was a pain and we gave up using it.
In addition the bed sheets are to much worn and with the fabric piling (although they were washed and clean) which was very uncomfortable.