This place has an excellent location, practically on top of a metro stop, and within walking distance of Alexanderplatz and Museum Island. There's plenty of space for 8 people (we were 2 couples and 4 singletons) and our host was very responsive to queries, and to our altered check-in time because of flight delays.
Beds were comfy, and there were plenty of towels and spare duvets. The apartment was warm (it's summer), but the windows open fully to let air in, even though it's high up (70+ stairs to climb!). There was noise from traffic and nearby nightlife, but it didn't really bother us much. The kitchen is fairly small, so there's not a lot of space for extras (no microwave), but it was perfectly fine for cooking up a few quick meals together in the evenings, and the Lidl supermarket was only a few minutes' walk away.
We had a fabulous stay :-)