I'm currently a UA frequent flyer based out of LAX, but will be moving with my family to LHR. Naturally oneworld makes the most sense out of LHR but I'm trying to decide if it makes more sense to join BA or AA. My main goals are lounge access and free long haul business class tickets for my family (either booking outright or through upgrading PE fares).

Some basic info about my expected travel / spend:

- Two to three paid business class flights per year through work to MIA or Latin America: total estimated spend $7-10k
- One to two personal flights to the USA per year in premium economy: total estimated spend $3-4k
- Two to three personal flights to Europe per year in economy: total estimated spend $1-2k

- Natural credit card spend: ~$30k/year

Based on all of that it seems like I could easily reach AA Platinum in my first year and Platinum Pro in my second year. Maybe even Platinum Pro my first year if I get an AA credit card. On the BA side it seems like I'd be stuck with Silver unless I went out of my way to add additional legs to my trips or do tier point runs, neither of which is really appealing to me. So for elite status the win seems to go to AA.

It seems like I would be earning 8-9 miles per $ on AA, while with BA it would be only 8 avios per £. Again this is a win for AA in terms of mileage earnings.

Am I missing anything here? Based on the numbers alone it seems like a no brainer to pick AA, but that feels wrong being based out of LHR. Will I be at any disadvantage by picking AA? Thanks in advance for any help here.