My girlfriend and I stayed for 3 nights over a weekend away in November. The apartment was impeccably clean with all of the modern amenities that you would require, with a lovely courtyard garden.
The location of the apartment is superb. A 25 minute walk to either Alexanderplatz or Brandenburg Gate. There are lots of nice restaurants, shops and bars nearby in Mitte. If you don't fancy walking then there are bus, tram and train links a stone's throw away! Moritz was very efficient, polite and professional. I would highly recommend this apartment to anyone who wants a weekend to explore Berlin!