I've been a loyal NWA customer all my life. Never had lost luggage and usually have had very professional service. Although flying their partner KLM kinda takes some of the shine out of their luster, lol, but I think KLM has absolutely extraordinary service (and some REALLY hot flight attendants, but I digress). I also think the Detroit hub is one of the best in the nation. Memphis has gotten quite a bit better too after their renovations.
On another note, I kinda wish some carrier would implement a shuttle system (hourly daytime flights) like the large Northeast cities mantain between Nashville and cities like Atlanta, Charlotte, and Memphis. The market probably isn't there yet (except I really could see it for Atlanta) but it would be a cool option to have