Well there aren't that many JW around the globe, 20 to be exact; 12 overseas and 8 within the U.S..

IIRC from my required reading of the good Marriott book, wasn't the designation given to some of the more luxurious locations as a seal of approval from JW once he'd stepped away from the top job. That part I'm less sure about.

The few international JW locations I've stayed at seemed little different than their Marriott counterparts and all things considered not sure I'd pay more just for the brand, but that's just me.