B
If there was an ability to do upgrades (EVIP for AA members) across to the OW carriers I'd give them an A.
Good:
Lounges, for the most part, are very good.
Decent worldwide coverage.
Reliable and pretty consistent.
Improvements:
A standard award availability tool that is reliable for multiple carrier routing. Each carrier could continue to maintain expanded availability for their elite members but it's a pain having to search 2 or 3 sites to create an itn before calling reservations.