I am going to try to remain focused on my review of the property, as I am not a huge fan of Venice. I'm a country girl and overly touristy areas are not something I enjoy...
The flat is in a great location, situated outside of the extreme tourist areas and just outside of the Jewish Ghetto which in my opinion was the best area we visited.
The front bedrooms were a bit noisy as they faced a canal with pretty heavy traffic (earplugs from our flight came in very handy). If you are used to city noise I am sure you will not be bothered a bit.
There are of course stairs to get to the flat. It is on the 2nd floor but there is no landing so you need to be very careful when entering/exiting.
The trash is a little tricky but I respect the recycling program and found it to work nicely. If you are tired and need to sleep-in, the trash collectors start ringing your door about 9:00 AM to let you know they are there.
The general feel of the flat was not cozy feeling at all, actually it was a bit sterile feeling. Between poor lighting and lack of area rugs it felt like you were staying in a basement with a nice kitchen.
As for cleanliness, it was clean except for 1 issue that apparently was only present in the master bedroom. Our visit was during the 2nd week in October. The weather was wonderful. Apparently, mosquitoes are an issue. I am uncertain if they are an issue in Venice in general (assuming they very well may be) or just in this flat.... the master bedroom had smushed mosquito carcasses stuck to the walls near the bedside lights. It was gross. I tried to clean them so I didn't have to look at them but they were not easily removed and I didn't want to damage the walls so I pretty much left them.
In the mosquito wars I can certainly see how they got there in the first place (get some repellent!).
In summary, good location, good amenities, great check-in hostess, good management/leasing company.
On the down side: mosquitos and a little sterile feeling (not homey).
All-in-all, I would recommend this flat to a friend just be prepared & enjoy Venice!!! ;)