I can only recommend staying with Mattia when visiting Venice. He is a very understanding host and when we had trouble with our arrival, he stayed relaxed and accommodating.
The apartment is situated in a lovely calm neighborhood, which allows to calm down after the hustle and bustle in the inner city. The walk along or through the Giardini back to St. Elena is beautiful and relaxing. The apartment is also very well equipped- especially the kitchen amenities make it easy to whip up a quick meal instead of having to dine out all the time. The only remark to make concerning allergies is that the sleeping arrangements come with a woolen blanket for colder nights, which, due to its structure, acts as a dust collector. Once aware of that, it is not a problem to handle though.
All in all, a very pleasant experience.