Location location location! Francesca's apt is located right in the center of the main island. It is on the San Marco square. i.e. You go downstairs and walk a few steps, then you are there. It has the view of the campanile out of three windows.
A few reviews mentioned difficulties with the check-in process, but it was not the case for me. The place was much easier to find than expected, and the self check-in was straight forward and hassle free.
Lorenzo was the local person I communicated with via Whatsapp. He always responded fast, with useful information. On my last day, Lorenzo even let me stay longer for a very late check-out.
The wifi worked perfectly. I had to work on my computer during my stay there (e.g. heavy video streaming for work). It was fast and continuous.
The air-con worked great too.
The photos on Airbnb don't do justice to the place. It is actually better than I had expected. e.g. I thought I would have a cramped and uncomfortable bed, but it was not the case. Some people might think that the place looked a bit old, but I think it is the charm and I was seeking exactly that experience.
The only challenge was the shower. The water was either too hot or too cold, and there was no shower curtain. It didn't bother me that much, as it was 30 degrees Celsius during my stay there and I was using the cold water straight.
All in all, I recommend this place and will come back here myself!