There was a time in the distant past when DTW had a really bad reputation; NW customers and employees would go to great lenghts to avoid connecting thorugh DTW. Then the new terminal was built and some roving customer service agents were hired by the airport (loden green coats, IIRC) and suddenly everything changed. Going through DTW became an extremely pleasant experience.

Recently it's been a bit more random IME since the merger, but I still consider DTW to be a very good expreience with generally very competent and very pleasant GAs, although I do notice that agents in the lounges, included the ones upstairs at the counter in the center A SkyClub seem to be able to do less to help than pre-merger. (Now the standard response to anything seems to be to direct the SC member outside to a service area.)