I have extensively with Northwest/KLM to various destinations in Asia and Europe, I believe their service is excellent. Food was great and the air staff was very professional and try to make sure would have a comfortable flight. Kudos to NWA/KLM for great International service.
But the US service is something totally opposite what you would expect from a major airline company. The customer service associates are very rude and they believe they are above their supervisors. The supervisors, if you are lucky to get hold of one are even more ridiculous than the associates. You would be on the phone with them for one hour and they decide to hang up the phone on you if the issue does not get resolved.
I have decided not to fly NWA/KLM on my domestic US flights because of the bad interactions that I have had with customer service.
I would not recommend to fly with this airline company within the US