W/o knowing your routing and, more important, the carriers you will be flying on (L class does not post to 100% to every FFP), it's quite difficult to give you some advice. Could you please post your routing and airlines?

General wisdom on FT is that AAdvantage is the best program overall. Anyway, this might not be true for every routing. The only thing I can tell you is to avoid BAEC since it's the "least generous" oneworld FFP if you fly economy.

PS: if you want to save some money, issue your tickets through AA instead of BA. They will charge you much less for the fuel surcharges than BA.