We had a good experience at Marty's accommodation. Unfortunately the washing machine was out of action (as Marty had advertised) and the laundromats nearby are a bit pricey so try to minimise the dirty clothes you bring with you from your previous city.
Fantastic location near central which makes lugging suitcases over bridges much more bearable (only two bridges from memory). Room itself is comfortable with everything you could need; we were there in winter and found it comfortably warm. The bathroom is clean although the shower was smaller than I anticipated and sharing with another couple can be inconvenient. No towel rack a pain as there were four of us there at once! Kitchen small but otherwise has everything you need. I think that the houses in Venice are quite small and I underestimated just how small they could be! The stairs are very difficult if you have a big 120 L suitcase like I did, definitely couldn't manage on my own so bring a small suitcase or a strong friend! Marty's husband kindly let us in but we never had any contact with Marty once we arrived which is very different to my other airbnb experiences. Marty left it open for us to contact her but all my previous hosts have always checked how things are going during my stay.
The one aspect of our stay that really was unnecessary is having to empty your own bin when you pay a cleaning fee.
Venice is simply stunning so we actually didn't spend much time at the accommodation! I would recommend staying at Marty's if you can't get a hotel because although it was a comfortable stay at a great location, things like the very steep stairs, emptying your own bin (!!) and shared bathroom at a price much greater than some hotels is worth considering.