Which Miles Program is Better For Me: Avianca's LifeMiles or Copa's ConnectMiles?

Hey everyone,

I'm new to this community and I need a piece of advice. I fly a lot and have never really taken advantage of airline miles, since I usually just buy whatever is cheaper at the moment. However, a friend told me I should be taking advantage of this and earn some miles in the process.

His first advice was to stick with a major airline alliance that suits me. I did a little research and I think star alliance is the one for me. I travel a lot to South America through Copa Airlines and can use United here in the states.

I was looking at the memberships and I have a little head start with 1500 of Avianca's Lifemiles and 4000 of Copa's Starmiles. So I'm trying to decide between these two frequent flyer programs and could really use some insight from those with experience. Which one should I stick with?

Any personal experiences or tips would be greatly appreciated! Thanks in advance.