Several other DL vs ?? in the linked posts here
http://www.flyertalk.com/forum/infor...help-here.html
Frequent Flyer Programs (FFP) are not equal.
1 (one) mile/point of FFP’s are not equal (just like currencies)
Each airline FFP can have different benefits from status.
Each airline FFP has different rules for earning and retaining status.
Each airline FFP has different rules for earning miles/points.
Each airline FFP has different rules to stop miles/points from expiring.
Each airline FFP has different rules for using (burning) those miles/points for awards and different copay $$ fees.
Each airline FFP has different rules for upgrades & different copay $$ fees.
Each airline FFP has different rules for lounge access (own & other airlines)
The grass is not always
greener over the fence