My family and I stayed at Ellen's place for three nights. We liked it very much! The apartments are very clean, there's everything you need - kitchen utensils so you can cook, washing machine and drying rack, hair dryer, iron, etc. The beds are very comfy! (I highly appreciate a good sleep during the vacation :)) There was a folding bed for our small kid, too. The location is just great, it's a hype neighborhood of Prenzlauerberg so you have lots and lots of restaurants, cafes and grocery stores within minutes of walking. You can easily reach the city center, too. The thing I liked the most is how surprisingly quiet the apartments are, because windows are facing the inner yard and not the busy streets. By the way, the yard opens with a key so it's a nice place to keep an eye on your bikes if you're traveling with them.
We were traveling by car so it was a bit tricky to find a parking spot, but not a big problem anyway. The house is located at the very edge of the paid parking zone, so if you want a free spot then just move a little further away from the center. We've managed to find free spots within no more than 7-10 minutes of walking. Anyway, Ellen gives you very detailed tips on parking options, as well as on reaching the place by the public transport, in advance.
We've enjoyed our stay, and we recommend Ellen's place to everyone traveling to Berlin!