We stayed at GianLuca's place for a short city trip and loved the apartment for this occasion. You can walk to Duomo in 15-20 minutes and have very hip restaurants and Cafés just around the corner. We didn't meet GianLuca, but his son who showed us around, gave tips for shopping and introduced us to the house rules. The Apartment offers everything you need - only negative thing to mention is the noise you easily hear from the streets and the corridor (slamming doors for example), which was especially annoying in the early mornings.
Nevertheless, we would definitely recommend this Airbnb for everyone who plans a short city trip and wants to explore Milan the whole day and would be happy to come back to GianLuca's any time!