Just dont expect PS+WP to be equivalent to SG; considerably less lounge access, for example, as recent discussion has demonstrated. Unlike an AC membership, WP does not allow lounge access except when flying QF (i.e. if flying CX, BA or JL ex-Oz you don't get lounge access, even if flying on QF metal on a codeshare!). So quite a big difference from SG lounge access rules!!! In US you can earn the SC delta for SG above PS for about the same cost as WP membership, fwiw.