The flat itself was nice enough.
However, you have to be aware that the building is very good at transmitting noises. If you plan to go to sleep early, you will be kept away by the family in the flat above walking around normally. This is not the fault of the family above. It simply follows from how little noise insulation there is between flats. In the same way, if you go out and party all night you might be woken up early, by the family above waking earlier than you do...
On another note, there are some very close metro station (Kleistpark, Yorckstraße). They are very nice and close. However, if you plan on going to the city center, the only station that makes a lot of sense is Bülowstraße. This one is ~900m from the station. Be aware of that.
Besides that, the flat is quite nice, if a bit minimalistic and not as comfy as it could be.