Wonderful experience with two kids (3-5)!
Spacious apartment, very comfortable beds, kitchen and dining area were very useful for breakfasts and some of the dinners.
Communications with the host was very easy and useful.
We were concerned at first that the several minutes walk to the ubahn would be problematic for our 3 year old (in December weather, much colder than our home), but it ended up being ok, and we sometimes used the tram to save a few minutes walk when she was tired in the evening.
We highly recommend, with kids as well!