Great points on AA. I used to fly with them a lot, and will have to see where my account is now with them. I will be splitting my time between the two cities, probably 3 return flights/ year and probably trips/year between NYC and Berlin.
In Re: to BA, Heathrow always struck me as a trickier airport to transfer through... however I suppose since both legs of the trip would be international there wouldn't be any terminal transferring and I could check thru?
Thanks for your insights