Communication with Lana was easy and very fast. Appartment is as central as it gets - and with trains/busses in every location, it's very easy to get around. Only "negative" comment is that the appartment is a commercial appartment, so if you are looking for a real Airbnb housing, meaning someones private residence, then this is not for you. Also the appartment might be a bit pricey compared to the amount of facilities in the appartment.
All in all - we had a very good time in this appartment, and I would recommend it to anyone looking for a great place to stay in Berlin!