Sorry about the confusion with my use of pronouns! My wife and I are flying, but she has left it to me to choose the itinerary, thus the 'I' in chossing the flights to take!
I have heard good things of both airlines in first, we were really please with the service and the food we got with BA in business on our DONE4 last year, in both 'old' and 'new club' so we were thinking it would only be better with the in first.
The BA flight would be on a 747, whereas the JL flight is a 777, so I think that they are all single seats. Both flights transfer through LHR, so we can't avoid it!
Our only experience in first is with CX and SQ.