The OW status of both is the same, though BA would prioritise BA Silver ahead of AA Platinum for any upgrades, just as AA do the reverse for their own members. Don't hold your breath, though, as BA doesn't upgrade status members in the same way American airlines do.

In view of your background, this looks like a straight 'which is better for me, AA or BA?' question. You'd need to weigh up the pros and cons for each, though I'd say it was likely that AA would be better for you. Think:

• no fuel penalty on AA awards
• better chance of upgrades with status on AA
• probably easier to obtain AA status

OTOH, with BA status:

• better lounge access, including AA, though if you have an AmEx platinum chargecard, you get AA lounge access with AA flights anyway
• possible 2-4-1 with Chase Visa