We had a great time at Giancarlo's place. It is very well situated for walking around Venice; we were just visiting a day and wanted to see as much as possible, and the proximity to the Rialto bridge was perfect for this. It is also very close to the water taxi line, which made arrival easy and would allow you to travel by boat just as easily as on foot. Despite being pretty central, it is on a nice, secluded side street, so there was no excessive noise at night.
Giancarlo was great as well - he met us at the taxi stop, walked us to the apartment and made sure we were all set before leaving. He also had recommendations for nearby food places, which was nice since there are almost too many to choose from and this helped narrow it down to a few reliable spots.
Finally, the apartment itself was lovely. It is roomy for two people, and is very comfortable. You can tell that a family used to live there - it feels lived in and loved, unlike some rentals that feel like they're just used as rentals and nothing else. We would highly recommend staying here!