We loved Studio MAV - it's a beautiful, spacious loft style apartment with a stunning high ceiling, high spec modern furniture and fittings, and well located in Porta Romana right next to the metro station with access to all of the highlights of the city centre. Lots of decent restaurants and cafes nearby too.
Maurizio's approach to service was excellent, with a dedicated mobile app providing all of the information needed for your stay, and regular messages to check that you were settled and had everything you needed. Would highly recommend Studio MAV for your break in Milan.