We stayed here for 2 nights as a quick stop over in Berlin and it suited our needs fine.
There was some confusion over how to reach the apartment door within the complex, but Ellen answered the phone first try and helped us out immediately!
If you arrive and go right to the apartment it is a quick journey from Schoenfeld airport with only 1 change.
The closest S-Bahn that runs into central Berlin is about a 10 minute walk away if that is a consideration (it was fine for us!), but there are many shops and coffee shops/places to eat nearby this.
The amenities within the apartment are great, and overall was everything we wanted for a short stay.