Ended up in a dispute mediated by airbnb. As you can see from my profile I have stayed in many airbnb's in many countries with very positive reviews. The biggest issue was the place was listed having air conditioning which was essential for our party on this trip in Italy in August. From the hosts responses it felt to me they deliberately listed that incorrectly as few people would stay in Italy in August without ac. Then the windows did not have screens which let in mosquitoes. The location although being central has the fresh fish market and fruit market right out the window. They start setting up at 5:30 am and are very loud. Add in the late night drunks through 2:00 am and we got little sleep. If it was cold or you could close the windows our trip would have been much different.
The other piece was I was not present at check in and my traveling companions checked us in. Traded emails with the host and without help needed to have airbnb mediate. They then sent me an email saying they had reported me to the police for not paying the city taxes. The money was on the table the whole time and they just had to pick it up. Their cleaning service does check in and check out. If they had come to the unit they would have known.
I would not stay here again personally. I would find something quiter either way as you can get most anywhere in Venice quickly.