Hilda'a apartment is bigger and better than it looks in the pictures. It's clean, spacious (I was staying there alone) and also has the amenities you will need during a stay. Especially if you'll be spending more time in the West-Berlin, the location is perfect. The U-Bahn Station Berliner Strasse is almost right at the door, so transport is not an issue at all. During the week after 1 am the night-bus drives to the same station as well.
Hilda is a very helpful host. If you don't speak German, language barrier might be a bit of a problem, but Hilda is willing to solve all the problems.
Overall, I highly recommend this apartment to anybody visiting Berlin.