Originally Posted by
con brio
500-milers are used for domestic upgrades on UA, but they're pretty plentiful if you fly enough. I read about the "unlimited domestic upgrades" but wasn't sure how common they are. Good to know a platinum is about 95%. I'm 15/16 on UA, so that's comparable to NW. I've noticed NW maintains a larger inventory of F seats, too, so the domestic upgrade seems to be a wash.
Just to pipe in on upgrades—I can probably count on one hand the times that I haven't gotten an upgrade, and that's as a Silver, Gold, and a Plat for the past two years.
You should also look at where you'll be heading from MSP—to small-ish midwestern cities, you're a lot more likely to find an F cabin on NW, who flies DC-9's to a lot of cities that only otherwise see RJ's.