Please advice me on South American programs..I found this test, that indicates that TAM is the best airline is the, followed by LAN and Avianca. According to Google TAM is the largest airline in passenger size, followed by LAN and Avianca. In number of destinations Avianca is largest, followed by LAN then TAM.

As a LAX resident I am member of AAdvantage, and if I move to MIA that will not change. But what if I move to Colombia, Brazil or Puerto Rico?

LAN is OW member, so I take it that I can collect AA miles, but will LA be a better program if I move? US Bank offers VISA cards. Is that a good option?

Taca is SA member and so is Avianca, but how do I figure out what program would be a best fit for me? US Bank offers a VISA card with both names on..

Estimated flying for now will be in Economy to the following destionations: MIA-BOG/ CLO, MIA-SJU, MIA-ARU/ AQA as well as between BOG-ARU-SJU & MIA-IOM, MIA-NAN.

If I only stay in MIA for two more year, or less, should I change programs?
Oh, and..a shot in the dark: does anyone know a scuba dive friendly airline to use within South America?

Thanks for all advice.