If I was starting from scratch and flying that routing, I'd probably go with AA and do a platinum challenge. Otherwise it's going to take a while to get to mid-tier and get lounge access.

Note that you don't currently get your status bonus miles on JAL, though that may change in the future.

Also, if your situation happens to have you buying more expensive/flexible international tickets, those would be easier to upgrade on just about any US-based airline.