If you stay with Nadia and Davide, you stay with kind and professional hosts that know what you are going to ask, before it occurs to you - we got detailed instructions on how to find our accommodations and all our questions were answered promptly and very kind. The rooms were big and the kitchen very nice. The location is perfect if you want to visit the Biennale - it is right by Giardini! Make sure to pay the small fee with the ticket that allows you to go and come anytime, so you can have lunch outside of the Biennale, or run back home for your forgotten smartphone.
In the apartment kitchen space is not really enough room for seven chairs around the table and I would not recommend to sleep on the fold-out sofa there, unless you are young and your back can take it ;-)