I definitely recommend Inge's place for your stay in Berlin. Everything was absolutely perfect!
The location is easy to reach by public transport and is close to some famous sights. The building is new and has everything you need. The flat was sparkling clean and nice to stay in. Apart from the comfortable bedroom with a huge bed, there is a guest bathroom and a small kitchen for a traveler. Everything is very modern and well-equipped.
Finally, Inge is an amazing hostess. Very sociable and interesting to talk to, it was a pleasure to make her acquaintance.
I seriously doubt there is a place that could be better than this one. Don't miss it!