My husband and I stayed in Mathi and Stefanie's apartment for 5 days and it was great. My sister were staying there for 10 days before it and she has also had a lovely time there. The apartment is in a central area, it is big enough for 3, very clean and comfortable. Mathi had a lot of maps and guides from Amsterdam available to us and he is a very nice guy!
If I go back to Amsterdam I would definitely stay in his house again!
Thank you much for everything guys!