Kelly is very prompt on responding to our questions; which is very nice and helpful. She met us at the apartment and give us much useful information regarding our stay in Berlin. Kelly is very hospitable. The apartment was clean, which we find very important. There are some recommendations however; the matras needs to be replaced (both my husband and I had pain in our lowerback after 2 nights). Also we prefer it to be dark in the room at night, so it would be helpful to update the curtains. We woke up around 6-7 because of the light coming in. There is also a lot of noice at night and early in the morning (people talking and cars pulling up, leaving).
An advantage is that the apartment is close to the airport (indeed after 20 minutes you have arrived at the address) and very closeby to public transportation (metro and bus).
All in all we had a very pleasant stay in Berlin.