Continental's got better benefits for all its Elites, including free unlimited upgrades on all levels, dedicated security and check-in lines, as well as the usual list of priority bag service, phone numbers, and such. The key is Continental's domestic First Class service is the best around, so if you do a lot of traveling within the 48 contiguous, and don't necessarily plan to fly a whole hell of a lot, i.e. Silver or Gold member, I'd suggest Continental's program simply because it gives you more chances to snag a FC seat than American, even with MRTC on everything but the 75 and the Airbus. It wouldn't hurt if you were of close proximity to the hubs in EWR
, or CLE
, or did a lot of traveling to any of them.
American offers an excellent top-tier program, patterned mostly off Continental, but IMO with more personal service. Their FC is decent, but the key for them is full EQM on all fares. Continental offers this on tickets booked from their website only, but outside of it, on cheaper fares you are out of luck. Continental still posts all flown mileage, but not all counts toward Elite status. From what I hear, American's reward program is easier to use, with much greater premium class availability compared to Continental's notoriously stingy offering, especially international. Continental offers superior premium class service, with the exception of First on their three-class 777s.
My bias is toward Continental, I'm an EWR
-based Platinum, but I recognize the fact that American offers an excellent program, especially for top-tier elites. I would say go with the program that makes the most sense from the standpoints of geography, how often you travel, and how you plan to use each program's respective benefits.