You didn't mention if you are originating from JFK or somewhere else? But guessing you are leaving from JFK I would fly through London. As a connecting airport HEL would be my choice but you are flying quite a bit extra compared to HEL or MAD and you are in much better spot in case of irregular ops with London. In case you happen to live in MIA it changes things since then MAD actually be better.

The business class seats on IB and AY are better than AA with AY being the best seat in my opinion (I also actually like the old MD11's). Service on board is best in IB in my opinion with AY coming in second and AA last. HEL is a nice airport but AY uses the old terminal at JFK which is pretty bad. New terminal in MAD is nice but I've never had good luck with IB ground ops and I felt like the new terminal requires one to walk WAY too much. Again, all of above is just my personal opinions and at the end of the day the shortest route with the most connections would be far more important to me than things like service / food on board.