I travelled as a solo traveller. Go for it. The place looks cleaner than the pictures. It's on the first floor. As others have pointed out, it's a beautiful spacious studio. There's Netflix and a nice couch as well. It's a 7 min walk from Duomo, close to many restaurants and trams. Also the bathroom is really nice. I wasn't expecting a bidet in Europe :)
Caveat: The place is next to a tram line so if you're a light sleeper, you might want to reconsider. Although the frequency is not too high, when the tram passes, you know.
David was kind enough to accommodate slight late checkout request as my train got delayed. Both of them were really kind and wanted me to have a great stay which I in fact did.
I'm not staying anywhere else the next time I'm in Milan. Great job Davide / Leonard. One suggestion: It'd be nice if you guys can keep a pair of bathroom slippers. There's no floor mats so it'd be good to have some slippers to keep the bathroom nice and clean.