Hey, as a NW Gold, I whole heartily agree, stay on those DL planes!
More reasons,
NW feeds you on flights blocked for more than 2.5 hours in first, this leads to obesity!
NW gives free internet to everyone in the world club, thus lowering your productivity by giving you plenty of opportunities to read Flyertalk instead of working on that report!
DTW is very easy for connections, so you don't get to make the "ATL run" after being delayed 45 minutes and arriving at the opposite end of the airport. Again leading to obesity!