Staying at Mario's place was a nice experience. The flat is really well located close to the centre area, easy to get around. The flat is really nice, perfect for couples. The place has a really nice terrace too which we could use for early breakfasts outside. Since there is no shade other times it was not suitable due to the heat we were experiencing during the 5 days we spent in Milan. The flat is well equipped, suitable for making your own cooking if you wish. Also there is always coffee and tea at your disposal too. I personally never had the chance to meet Mario, but talked to him several time as he was always prompt in his responses whenever i had any questions or little issues and was always attended to them accordingly. Check-in and out was well organised, no problem.
All in all i would recommend to stay at his place any time.