I'm in the unique position to have consumed about all of my FF miles on various programs, so I can essentially "start from scratch". About 90% of my miles come from credit card charges, not actual flying. About 90% of my award redemption is for flexible international leisure travel in F class.

I was just about ready to commit to AA when I discovered they have some unique rules about transatlantic routing being on aa metal. I further learned that AS does not have this requirement, and appears to offer a nice mix of international partners in several alliances.

Furthermore, premium class AS redemptions on partner airlines tend to require fewer miles than AA redemptions.

I fly out of LAX/SNA so both lines have an equal presence in my area.

I already have an SPG Amex, but I need a visa/mc solution to supplement.
What would you do?

(I apologize if this is in the wrong forum, but I could not find a better place.)