It was a great experience staying in Berlin!
Unfortunately I didn't have a chance to meet with Zain but I had nice communication with his flatmate - Miro. He recommended me a lot of interesting non-touristic districts in Berlin. Also Zain provided very descriptive guide related to restaurants and bars in Prenzlauer Berg.
The apartment is really very large and quiet, here you can find anything you need to stay with comfort.
Location is also very attractive. S-Bahn is in 2 minutes from an apartment, in 5 minutes you can find several groceries (Rewe, Penny) and also it's a district with a big amount of nice cafes and restaurants where you can taste healthy breakfasts. If you want to have some fun in the evening you can visit one of the bars nearby.