Which Star Carrier to Join? Help!
 

Currently UA Gold ....soon to travel extens. SQ/NH/LH/AC in JC or FC, which carrier offers the best mileage redemption, upgrades, service, status, etc. Have been 7 yrs Exec Plat with AA and need a change.

As a generalization, I'd say to go with the FFP of the carrier on whose metal you'll spent the most time (presumably, the one you'd prefer).

Having said that, however, I'd refer you to this very recent thread for a very informed discussion of your very question. Most to the point are posts #4 to #6.