For people that buy J tickets, BA Executive Club is the easiest program to hit top tier with North America travel. For example, an existing Silver card holder needs 500 points to requalify. F class on CX between JFK and YVR gets you 180 points PER SEGMENT. And BA's top tier members get free lounge access (and unlimited free drink chits) in all Admirals Clubs, and Flagship Lounges when travelling internationally.

Food for thought...