Alaska is probably going to be the most generous in terms of earning redeemable miles, especially on Business Class fares. However any status you acquire won't do you much good...

What you don't want is AA... reward chart is worse than AS, and status is low value unless you fly AA domestically and get lucky with upgrades.

JAL has a lot of potential, but I've never dug into it in enough detail to come to a firm conclusion.