If you can get a Chase 2-4-1 ($30,000 in spend on their card in one year), then you can do JFK-LHR-JFK in first for 120,000 miles [and $1850 in taxes] for TWO people round trip. That's much better (mileage-wise) than you can get on AA (125,000 miles per person) although AA has lower taxes if you use their own metal).

Putting two long hauls together is also possible because the 2-4-1 is good for your whole itinerary (including any stop-overs) and you can use your AA miles for the return. So you can go JFK-LHR-JNB or JFK-LHR-DEL or BKK or some other fun place in first and then return using your AA miles. The cost of a one way in first to those places from LHR varies from 60,000 to 105,000 depending on distance plus you have to add the JFK-LHR leg in first (which is 60,000) (plus whatever taxes cost) but having a 2-4-1 makes it a better deal.

I posted a thread in this forum about a week ago comparing and contrasting the redemption process on AA and BA which might be of help if you want to search for it.