Martin's apartment offers very good value in Berlin—easy to get to/from and perfectly adequately appointed for a short stay. The building is quite large (like a big college dormitory, almost) but by the end of our trip it definitely felt like home. We were able to find great breakfast, lunch, and dinner spots within 10-20 minutes on the metro easily, but if being able to walk downstairs to your favorite coffee shop is important, I would suggest looking elsewhere. For us, it was great, as we spent most of the day outside roaming the city anyway and were very happy to come home to Martin's spot each night.