I highly recommend Mattia's apartment for various reasons, which I'll share, but it is dependent upon what things are important to you.
Location: I found it to be centrally located, as it is about a 10 min walk from train station and 12-15 min walk to the city centre, such as Piazza Maggiore. Though it is on a busy, modern street in a high ride building, it was quiet at night. We could hear our neighbor's TV and talking in early evening, but it wasn't an issue later when it was time to sleep.
Mattia is readily available, good communicator, though this apartment does not have self-check in, such as a lock box. Mattia met us at the door of the apartment building, and personally let us into the apartment and gave us a tour.
The bed and pillows are comfortable, which is important after walking/touring all day. Mattia includes personal touches such as shampoo/conditioner, paper towels, water in the refrigerator, etc.