I visited Milan together with my girlfriend, and we're both very happy with Marta's apartment. Location is great, few minutes walk from the Piazza Duomo, in a rather quiet area with a proximity to the luxury stores (hey, it's Milan) and nice restaurants.
The apartment was just like shown in the pictures, very clean, freshly renovated, with everything you might need for a weekend stay.
Marta was replying to my messages at any time of day (or night), answering my questions and providing tips on where to go or what to eat.
If we'll come to Milan again, I'm sure that I'll check the availability of this place first.