We had a nice time at Yi's apartment. The flat is situated pretty good: The neighbourhood is not too busy, which we liked, and still we could reach interesting places quickly.
We could reach the flat quickly from the closest M3 station as described and we were able to walk to the Duomo in short time, too.
Inside the flat was everything we needed for simple cooking, one bathroom and a second shower in another room. Moreover, it was nicely decorated.
Check-in and out went smoothly and Yi responded quickly to our messages. At the day of our departure, we could not leave as soon as planned due to our travelling schedule. Yi answered fastly and kindly allowed us to stay for another hour.
Thanks a lot for your kindness and flexibility! :)