I stayed in Berlin for 5 days and Gat Point turned out to be an excellent choice.
The location especially is ideal, as the Brandenburg Gate, Potsdamer Platz, Under den Linden, Gendarmenmarkt and many other sites are all a stone's throw away. If Berlin nightlife and clubs is the focus on your trip, do bear in mind that these are located well outside the Mitte, but are still fairly easy to reach via U and S-Bahn.