Great stay in Berlin. The apartment was more than large enough for our group of 5.
The street is busy, so the front bedroom can be tough later at night, but the building itself was quiet.
Rooms were spacious, and the location is central to all. Plenty of restaurants and night shops are within walking distance.
Biggest downside was the wifi, which was basically nonexistent in the apartment.
Check-in was a breeze and the guys stored our luggage while they turned our apartment over.