5 advantages AC has currently:
1. 90K to Europe, when on UA and LX no YQ it's amazing (especially last minutes, where the YQ falls off as well).
2. No close in booking fees. Worth for domestic last minute RT's
3. Flat rate lap child which is amazing. (had times where UA and US wanted $2900 for the lap child)
4. 2 stop over + open Jaw.
5. a lot better availability on SQ and some others (IE, SIN-PER/BNE/SYD/MEL where SQ J is almost non-existent on UA, it's all over AC)
IME they never enforced MPM, especially over the phone.