I agree with almost everything that's been said above - I'd suggest that timing matters more than actual product. Ignoring that...

For the eastbound leg, I'd choose BA's 747 upper deck for the privacy. However, there is a little more ambient noise than the A380/789.

For westbound, I'd be tempted by the AA 777-300 but that is the only product listed that I haven't yet flown on... the direct aisle access and T3 lounges would tip the balance, but they are worth more to a solo traveller than a family.