Alan and Kasia's place was great. The apartment was clean, nice, and had everything we needed for our trip in Berlin. Alan met me at the apartment and gave me lots of good information about the neighborhood. They left a good binder with lots of good information on bars, sites, restaurants etc... The location was great, right near the M4 tram that goes straight to Alexanderplatz, and the S42 ring-bahn, which takes you everywhere. Totally recommend this place, it was fantastic.