Summary: I wouldn't stay at Carlo's place again. The flat was fine, clean and as described but Carlo was not accessible and we had to wait for the caretaker of the apt to let us in. The flat was also a little out of the way.

The Good: The apt was clean and as described. It was located in the Barona Neighborhood, near bus stops and metro stations. It was in within walking distance to everything you needed.

The Bad: We never met Carlo in person and was only accessible via text/calls (not email, at least w/o a lengthy delay) which which was impossible for us since we were travelling from the States and did not have an international calling plan i.e. we could send emails but no texts/calls. A caretaker arrived after we did to let us in to the apt and show us around.
We actually had two separate stays at Carlo's place, on the way in, and on the way out of Milan. On the way out we had arranged to arrive at 9 PM. No one was there to let us in and I couldn't get a hold of Carlo due to the above mentioned contact method. When he did reply (via airbnb) which sends texts to the host and he could receive in real time, his responses were outright rude. He stated that he told me to contact him via text or call (even though I repeatedly made it known to him I wouldnt be able to) and that to "remember Airbnb is not a hotel and there is no reception" while we waited in the hallway of his building for a half hour for the caretaker to arrive to let us in. Not how you want to spend your time when on vacation.