My home carrier is SK and I therefore try to fly as much on *A carriers as possible. Currently I am looking into some summer travel from CPH to SFO. It's expensive!

It turns out, however, that a biz ticket on AF/DL is only slightly more than an economy ticket on SK. So I am strongly leaning towards that option. Now the question becomes: which ST program should I sign up for to credit those miles to? Is there a program that could tempt me to fly more ST out of CPH? Thank you very much for any good advice.