I had one 3-day stay at Numa, Potsdamer Platz in Berlin.
Overall considering facilities and location this accommodation is reasonable value for money, especially if you are on budget.
There were many problems however, and I will never choose this accommodation again.
1) The place is dirty, especially room floor and bathroom.
2) This “hotel” has no reception (you get code and all instructions online). When I arrived at the front door, equipped with all codes and entry instructions, I was fumbling with the keypads for about 10 minutes and was unable to enter building. Fortunately another guest arrived and showed me how to operate doors. Each time you need to go in or out, you need to enter 5-digit code on small key pad at several doors.
3) This is very aggressive business. In total they sent me over 40 messages on email and phone for this one stay. They want city tax payment well in advance and they sell other services. You must fill forms and surrender all information in order to receive code. 3 months in advance, they started sending me daily threatening messages that I must register online or I will not be allowed entry. Then I must fill online forms to “successfully check out”.
4) They advertise “free gym access”. When I arrived, I spend several hours, but was unable to gain access to free gym. The web link takes you to a landing page for a 3rd party which is a major fitness suite provider in Berlin. You become victim of another aggressive business attempting to sell you