Had a super stay at Nena Apartments! The location is brilliant - only a block from the station to get the train right from/to the airport. Really close to central Berlin - we walked a lot and it was no problem but there's so much public transport options close by. The apartment was clean and comfortable, with really helpful staff. They accommodated late check in and we were able to leave our luggage after check out.
Would definitely recommend a stay here! Nothing bad to say and couldn't think of anything else to make it better.