We had a nice stay at Intervarko hotel.
The room was clean and the place is near a tramway station, fine to go in Berlin city center. The woman at the reception was really nice and they gave us the room earlier.
However, don't forget your wax earplugs if you want to have relaxing night. Actually, after 8 or 9 AM, there was noise (the vacuum, construction work, hand dryer, hair dryer..) because of the building isolation. Bring also a sleeping mask, curtains are tiny and don't cover all the window.