There's no doubt that AA long-haul are much improved.

Consistency is the challenge with BA as with all airlines. You mention the inflight entertainment. That can actually be really good on BA or completely shocking depending on the exact aircraft. Assuming you flew via London AA use their best planes so you will do ok but if you fly e.g. to Edinburgh on an AA 757 you might have a different experience (overhead monitors I think).

BA has improved too recently albeit from a low base and from mistakes of their own making (those Mars Bar second meals). Breakfast in Y or W is still abysmal.

Still, I remember when I started flying seriously how hard I used to try to avoid AA yet stay in policy. BA Club World was the bees knees and you either had their pre-flight dining or cubes of cheese in the Admirals Club. Those days are a distant memory now.