Delta Airline is so so. Their US domestic service isn't as good as it used to be before the mergers/ acquisitions of various US airlines from 2005-2011. Their Pacific route has better service, but this is probably from the competition from JAL, ANA, KAL, Asiana, Singapore Airlines, China Air, etc. They keep Delta, United and AA on their toes.
Apologies for the English comment, I found this review while researching flights from the USA to HND. Interesting to see that they staffed the plane with what seems like a large number of Japanese crew members. Usually when I fly internationally, USA-based airlines will have only 1-2 flight attendants who are not American for those who don't speak english.