My group of 4 thoroughly enjoyed our stay at Nena Apartments. It was located in a very central area - an easy walk to Alexanderplatz which had lots of shops and eateries and close to two stations so we could get around easily. The apartment itself was clean and exactly as pictured - modern and spacious. Our only feedback is that the wifi did not work at all so we had to use our mobile data and that the shower drain filled up at times which flooded the bathroom slightly.
Overall - would recommend.