I think Virgin Atlantic miles are underrated.
It's borderline impossible to get a full family on award miles from LAX to Lon (or even LAS to MAN). They regularly have 2 upper class, 5 economy, and 5 economy plus seats open for flights. Economy plus while a slight rip off is always wide open, so if you need to score 4-6 seats, it's one of the few options out there.
BA is the only other airline to have so many seats open out of LAX, and the fees are worse on BA.