During my last visit to Berlin I stayed in three different hotels, and by far hotel Atlantic was the most convenient.
Pros:
1- ten minute walk from subway and shopping mall.
Four minute walk from supermarket and McDonald's.
2- Free wireless Internet, fast enough to stream netflix.
3-Price of hotel is cheapest around and if you pay cash you might get a discount.
4-breakfast is included you will get cereal milk, orange juice, ham, bread, yogurt, fruir boiled eggs and sausage..
Cons :
1- the blankets as other European hotels as small they aren't long enough.
2-elavator is shut off at 9pm ( there is only 3 floors) so plan accordingly.