I can confirm now both JW Phuket and Khao Lak give full buffet breakfast as plat amenity, and both breakfasts are excellent. I personally far prefer Khaolak breakfast because of variety but Phuket one good and had fresh squeezed juice which was excellent.
From a plat standpoint, Phuket offers very little while Khaolak is more generous (1 drink per person per night and free shuttle).
Beach at Phuket nice to walk on but not really incorporated into resort like Khaolak. Phuket's pools tiny in comparison but overall has a more luxuripis feel... Khaolak seems more like a giant Sheraton to me. Service at Phuket was subpar, with staff never smiling, almost machine like. Khaolak service friendlier.
Mixed on both resorts. I'd go back but not dying to. There are other resorts out there I'd like to try first. JW Phu Quoc far superior, as is LC Vana Belle.
I had higher hopes for JWs to be more luxurious yet still be large enough for fun for little ones. Not quite luxuriois enough, not quite fun enough.