Depends what you are trying to achieve, if status or redemptions or both.
M&M is a program for people who fly in premium cabins on full(-ish) fares. If you routinely fly "P" or economy, you have to look elsewhere.
You are located in south america, so M&M brings you pretty much nothing. Look carefully at your flying patterns and at the alternative *A programs you can use to obtain status and spend your miles with.