Mario's apartment is excellent! He is a great host as well. It's my dad's birthday and he left us with a nice bottle of champagne and 3 huge bottles of water. He recommended this pizzeria called Antica and it was great that we went twice! He also showed us where the tram stop is, short walking distance (Tram 3 and it ends at Duomo about 20 min away). There is also a local gelateria called Casimiro (so good!). Navigli district is about 5 to 10 mins away. The apartment is huge! Well lit, clean, smells good. The building is safe, there's a locked gate.
Cons: 1. In one of the bedrooms it's right next to the main road. At night you will hear the tram (which you cannot really avoid, I'm used to city noise) but what made it worse is I'm not sure if there is construction or what but there's a loud noise literally around 3 or 4 am on both nights that we stayed. I hope that is only temporary.
2. I move around a lot when I sleep and I find that the single bed doesn't stay put. It felt like I'm in a hammock lol. I moved in the couch area and it's so much comfortable to sleep there.
Overall we enjoyed our stay! Thank you Mario!