Excellent location, well suited for prolonged living and good internet!
The Berlin-Mitte neighborhood is at the center of the city. There are supermarkets, coffee shops, and restaurants near the hotel. A lot of them also work on Sunday and during holidays.
The hotel room is spacious enough, has a desk suitable for working and additional table. There's also a kitchen cabinet suitable for cooking. The only issue was that the windows frames are a bit old and don't isolate well outside temperature and noise.
Internet was 50 MBit/s during the day and enough for working. In the evening the speed would drop as I suppose everyone is home.