Must to avoid. This was a terrible experience - except for the superb service we received from Airbnb staff.
Angelika was a terrible host. She did not respond to messages regarding our arrival time. When I finally tracked her down, an hour before our planned arrival, she reported that a friend would be meeting us at the flat. When I phoned that friend (who was doing her best to be helpful), she was at work and would not be free until the evening. We had to drive to her place of work through London traffic to collect the keys, and this delayed our arrival at the flat by a full two hours.
When we got there, we couldn't figure out how to get in the building and had to call the friend for instructions. We stepped inside a non-smoking flat that reeked of cigarette smoke. There was an ashtray on display on the kitchen counter. We called Airbnb immediately, cancelled the reservation, and set about requesting a refund - which we got in full, thanks to superb staff.