For economy, the BA 747 will be less cramped than the AA77W, unless you can get into AA's MCE section.

AA is lenient on carry on allowances.

Yes AA provides pillows and blankets on transatlantic flights.

On transatlantic flights, AA gives soft drinks, beer, and wine at no charge. Liquor is extra.

Reading trip reports, it appears people actually prefer AA's economy food to BA's but that doesn't say much.