I completely concur with the assessment posted by Mr. Nice. The ability to walk to the airport and both the Metro and DSB train stations is extremely convenient.
For the CP, you would call the free shuttle, as the Metro line serving the hotel (line M1) does not run to the airport. Also, the DSB train station is outdoors and a slight longer walk from the airport lobby:
http://en.wikipedia.org/wiki/File:%C...ad_station.jpg