My analysis had nothing do with which one is better! My analysis was simply that their FPP programs are quite different due to the differences in the countries they're based in, and I see no reason why the FFP program (which has nothing do with in-flight service quality!) of AA would change to the way some FFP program halfway around the world works.

The OP was talking about the diffference in FFPs, not the different in service aboard the flights.

(You can earn in any partner's FFP when flying either AA or Finnair. But you can't choose to fly Finnair planes from LAX-DFW any more than you can choose to fly AA planes from HEL-OSL.)