This probably isn't the right topic for Mileage Run discussion, but I throw in my $0.02 before this gets moved.

First of all, every program is free to join, so I assume you mean which program should you begin using exclusively. If you travel on an airline, you should absolutely sign up for their frequent flyer program, because, as I said, it is free.

It typically depends on where you live, where you travel, and what you classify as "good" - i.e. what perks interest you the most.

Typically, if you live in a hub city, you should go with that hub if you'll be doing frequent travel. If you do not live in a hub city, then you have some more leeway. All the carriers will have service to S.A., but you could do some price comparisons, to see which has the best prices.

The key factors anyone will need to offer up any helpful advice will be:

1. Where do you live?
2. What perks interest you about a frequent flyer program?