I stayed here for a little over a month with my family (wife and a three-year old) and would recommend this apartment to anyone who would like to be near the center of Berlin. The neighborhood was quieter than I expected given the location, and all of the major parts of Berlin were easily accessible via the U-Bahn station near the apartment. The Edeka Supermark in the same building was also very convenient.
The hosts were a pleasure to work with. They were readily available to help with anything necessary, but not at all intrusive. I would definitely work with them again.
There was only one drawback, but it wasn't a fault of the hosts. A few of the neighbors would smoke as late as 1am and the smoke would drift into the apartment through the open windows. This may be unavoidable in a European city, but considering that my wife was pregnant, it was a nuisance. It was too warm to keep the windows shut in the evenings so on a few evenings in addition to the smoke, we were treated to some loud music from other neighbors until about 1 in the morning.