To add to pinniped's point, as one of the strengths of the CO and NW programs is unlimited domestic upgrades for elites, jumping to them out of CHS doesn't make a lot of sense since your first leg will always be on an RJ. Also, assuming you do a fair bit of international travel to hit 150K as a leisure traveler, NW and CO have pretty significant limits on which int'l fares are upgradeable, even as a top-tier elite