In my opinion, I think UA MP is one of the better one for mileage accrual. If you reach Premiere Executive level, you can double your miles every time you fly. And you get mileage accrual with all classes of fare. Unlike many of the Asian carriers, they do not allow you to accrue miles with the cheap fare class. That's the reason why I drop Krisflier and EVA. I made 1 million miles within 7 years flying from SFO - SIN and SGN.