Had a fabulous 3 week stay in Mario's apartment. Didn't actually meet Mario but he quickly responded to any questions he had. Carlos, who was looking after the flat was friendly and very helpful.
Very well equipped, we cooked at home most nights and also entertained family on a couple of occasions. Very comfortable bed, great bathroom with a lovely shower and plenty of hot water.
Great location, one minute to the underground and so many bars and restaurants close by. We loved it and it felt sad when we left because it was starting to feel like home.
Thoroughly recommended and the easy parking in the heart of Berlin was a real bonus. Would not hesitate to return.