For your information, there are not "family accounts" that allow pooling of miles.

Please note that these are "Frequent Flyer" programs, meaning that they are designed for people who fly alot in order to garner their loyalty.

Too many infrequent flyers worry about "which program to join...."

If they are infrequent flyers, they are probably best served by flying what ever airline has the cheapest fares to where they are going. The actual choice of program within an alliance will probably not be an important issue as they will likely never earn enough miles for a free ticket, or if they do, they will have paid more unnecessarily for the tickets in order to qualify for the free flight.

That said, if they are flying on AZ, then I would suggest AZ's program.

Cheers