In general it's a roomy apartment in a great part of town. The bathroom is fine and the kitchen OK, but it is an expensive stay for the condition it's in. Here are a few of the issues:
The air conditioning in the bedroom is so noisy it is not possible to sleep while it is turned on, but it's not possible to leave the windows open else the room fills with mosquitoes. I saw that other reviewers had commented on this, and its still not fixed.
Other things need fixing, cleaning, replacing. The host has been notified about the smaller issues. The sofa is not very appealing to sit on and needs a really good clean or new covers.
On the last night the water heater stopped working and there was no hot water for showering or washing up. As it was the last night and rather late, the host was contacted about this on departure. I was told this happens every few months due to water pressure inside the heater. But in that case, it would be a good idea for the host to get it properly fixed or replaced, as it would not have been fixed instantly had it happened in the middle of my stay.
If you're looking for a quiet stay it's also good to remember that overlooking a canal in Venice may look attractive, but is particularly noisy: its like a main road, where barges and motor boats pass through the day and much of the night. This is of course a problem for many apartments along canals, but this one seems more busy than some of the others with delivery barges as well as locals own motor boats. (The people downstairs, or neighbouring house, also had a very loud party starting around 23.00 lasting until the early hours. Luckily this only happened once, but highlights the problems of old buildings without any isolation).
Arrival:
The host was not possible to contact in the days leading up to the trip. The phone number on airBnB's page didn't work and after two online messages I still didn't receive a reply. This is problematic when there is no actual street number listed on airBnB, especially when the phone number doesn't work. Less than 72 hours before departure I was very concerned and eventually contacted airBnB, who then contacted the host on another number. (Note: AirBnB were extremely helpful!).
After this there was a nice correspondence with the host, who was very welcoming and explained they were away when my messages were sent. The check-in was fine. The lady who met us for checkin was nice and, and the host allowed us to arrive earlier than the official checkin time of 15.00, which was also convenient for us as we had an early flight.
But this pre-departure stress is unpleasant: its important for hosts to reply and ensure contact information works. I have been stranded in Paris in a previous similar scenario, so do not feel I am overreacting about this.