I really enjoyed my stay at Wil7. The service was communicative, kind, and accommodating. The room was basic but had almost everything I needed. It was clean, quiet, and I enjoyed that it felt like a small studio apartment. Overall, the other guests were mostly older (50s+) and everything was very quiet. I would recommend staying here to solo travelers or older couples who need a good home base while exploring Berlin. It's centrally located and only a 5-10 minute walk from multiple metro stations.
One thing I will note is that if you have to check in outside of the front desk working hours, your keys will be left in a lock box and it can be a bit confusing to find your room (as the hotel is located in the same building as residential housing). The desk provided instructions for me, so just be sure to read these before arriving so you don't get lost.