It was a really nice stay. The apartment is very clean and modern, which is a plus.
There is a bus stop 5min by foot, which brings you to the centre of Venice in 15min.
Mestre is a really nice part of Venice, with restaurants and shops.
We were alone in the apartment 4/5 days, and we met the host the last day of our stay. He is very welcoming and nice.
I totally recommend this apartment :).
Note: in Italia you have to pay a tax (visiting tax or something like that). In Venice it was 4€ per day per people with a maximum of 5 days. It is not included in the Airbnb price, you have to pay in addition.