And now for a different perspective:

I flew Lan Chile in 1998 Lima - Santiago - Easter Island - Santiago - Antofagasta - Iquique - Arica - La Paz.

Every flight was on time and the service (in Economy Class) was outstanding (far better than most international trips I have taken on US airlines).

Among people who fly frequently in South America, the general consensus is that Lan Chile is far and away the best South America Airline. I am not doubting any part of the ordeal recounted by the previous poster, but I believe his experience with Lan Chile was very, very unusual.