I give NW the edge on partners worldwide, though the CO/America West one might indeed be more valuable in some places. Hopefully HP stays in business.

NW can also get you an HA interisland award for 5K rather than 10K on CO. They also have the edge in online booking of awards.

OTOH, NW's excluding of CyberSavers and miles + money fares from mileage credit is worrisome. NW management has never been as committed as CO to making the FF program an industry standout, IMHO.

The real wildcard is mileage-earning specials and mileage sales. CO is in a drought on them now, but I would still give CO the edge there.