I really enjoyed my short stay at Jan's flat in Kreuzberg. The apartment is small but has everything necessary for a brief visit, from a well equipped kitchenette, to basic toiletries and towels, etc. The check in experience and communication with the host was very easy. And the location of the apartment is great.
While there is internet access, if you're planning on working during your visit and will require a solid connection for video calls, etc, you may need to rely on your own data.