Between November 12 and 18, 2012, US Airways is offering 5,000 Preferred Qualifying Miles for new or renewed US Airways Club memberships (and the $50 initiation fee is waived for new members). Simply use promotion code 5KPQM when applying. Given that it’s the end of the year where many are in a bind for PQMs I can see this offer being tempting to some.
I still think the American Express Platinum card is a better value for access to American, Delta, US Airways, and Priority Pass lounges, given that the annual fee is similar in cost to a single lounge membership and gets you a ton of additional benefits (Global Entry fee waiver, $200 airline fee credit, access to Fine Hotels & Resorts, etc.).