B+
Pros: Definitely the best program among US airlines, especially in controlling free upgrades (limited to EXP), amount of available seats for upgrades and allowing upgrades from virtually all fare classes; never had issues redeeming miles; 100% bonus miles for Platinums; all miles count towards MM status.
Cons: Upgrade co-pays; inability to book mileage upgrades online; inability to view award availability on partner airlines; paid cash upgrades at the airport which diminish the Business Class/First Class experience; elimination of stop-overs on award tickets.