Our host, Stefano was very responsive throughout our stay (email, sms, phone).

The apartment is located in a very well maintained apartment building (spanking clean actually!) with the typical Italian inner courtyard. The apartment itself is very nice, spacious, nice furniture and lighting, comfortable mattress (important after the daily mileage covered! :) Nothing brand new but we did enjoy its lived-in atmosphere, makes you feel like a local. It has all that's needed for a comfortable stay (incl. washing machine and dishwasher) and very important - 2 Moka coffee makers :) (just buy your espresso from the specialty coffee shop a bit further down Castaldi street!) There's also a Carrefour express on the same street (5 min walk), and a large supermarket, Esselunga, near porta Venezia metro station (15 min walk)

The location of the apartment is very good, 1 metro stop from Milano's Centrale railway station and 2 stops from Duomo metro station, both directions are also walking distance (10/20min). If you jog, the apartment is right next to a very nice park so that's solved too.

All in all I don't think you can go wrong with this apartment.