I did this bonus a while back... of course, I was able to put about $6k of my required spend through AP and Serve, while the rest of it was legitimate spend.
But 150k points for $450 plus some minimal additional costs...
Dont forget you also get $200 (and really $400 since you can do it each year) in airline reimbursements, plus 10 free GoGo hot spot passes, plus the other perks of a Plat card.
To me, its def worth it, but to each their own.