Nikolai is an extremely kind, friendly and considered host. He makes you feel very welcome and "at home". The apartment is bright, clean and well located. Prenzlauer Berg is my favourite neighbourhood to stay in and all the good coffee shops and restaurants are are in walking distance. Alexanderplatz with all its train/U- and S bahn connection is 10min away in tram.
I can only recommend to stay at Nikolai's place :-)