Katrine is a great host: she always answered very quickly and she is very flexible. For example, as our plane was delayed we only arrived at 2am but she found a solution. She also allowed us to leave our suitcase in the apartment instead of leaving at 11am, as planed (it helped us a lot as discovering Copenhagen with our suitcase would not have been fun).
The apartment is very nice and the localization is perfect (very close to the very center of Copenhagen and direct from the airport by metro).
One thing: the apartment smelled cigarette (even the bed sheets and the towels) which is very unpleasant for non smocking people.
But I think it was a one-time issue, and Katrine apologized many times for this.