Justine's place is amazing and I would stay here again.
Location - it is in the heart of the old town and yet in the neighborhood that is a little less touristy. It is a quick walk to the Rialto bridge where there is a water bus stop and a quick walk to St. Marks.
Cleanliness - spotless. Comfortable. No weird smells.
Amenities - kitchen was well stocked and had plenty of coffee, sugar, napkins, olive oil, salt - things that many Airbnbs lack. Washing machine - be aware it's a long cycle but it works! Television with Netflix! Hot water. Heat worked nicely. Heated towel rack!
Comfort - it's a very nicely furnished and decorated apartment. And it is newly renovated. We were very comfortable there.
Communication - Justine always responded promptly. Her mother picked us up at the Rialto bridge to take us to the apartment. We also ate in her restaurant - which was an excellent choice - food and wine was amazing and we were treated like family!
One note - there are a couple flights of stairs to get to the apartment and no lift. Shouldn't be a problem for most people but it is worth noting.
If this Airbnb is available - definitely go for it. Only regret is that we could not stay longer.