Firstly, Maciej was a great host - you can tell that he prefers to read than to watch tv series! Very knowledgeable and informative about the culture of Berlin (and other countries besides). A pleasure to hang out with.
The apartment is airy, bright, immaculately clean, and not without its ability to inspire. We came back in quite late some nights, early others, and always felt that we had privacy and flexibility.
The apartment is in a good location. We cycled there in about 8 mins from Alexanderplatz, and were able to easily get the frequent trams from the stop which is about 3 mins walk away (Central Station about 15 mins, Alexanderplatz very close as well).
Overall, a very pleasant introduction to Berlin from an amiable, polite and magnanimous host.