For an early morning gathering of business people from Wilmersdorf - there it is another one in Mitte, Rocco is not such a bad choice. It is situated close to the U-Bahn, there are plenty of places free and there is a lot of light.
The design is not the strong point of this bar as it looks very similar to many kitsch American-style bars from Texas. The menu is 'international' with pizzas and hamburgers and nachos and various types of breakfasts. The prices are pretty high, compared with what you can find in other good looking places. I did not try anything and do not have any intention to do it any time soon, but my simple cup of cappuccino was around 2 Euro and something.
The service is pretty good with friendly faces and fast delivery and the restrooms are clean. If you are rather the 'old school' and you want to network with your business contacts, you can use such a space. Otherwise, there are plenty of places to rent in the hip new office buildings in the East.