This really is an excellent apartment. The space is huge, there were only 4 of us, but you could fit twice as many people comfortably. The kitchen/dining room is the best feature; it's a great space to get everyone together. The sizeable bedrooms, two bathrooms and a second kitchen(!) all make for a great experience.
The apartment is nearby to the local U-bahn so access to all of Berlin is really easy. The local neighbourhood has places to eat, drink and go shopping if you don't want to venture too far.
The four nights spent here were great and I'll be recommending this apartment to anyone visiting Berlin.