$500 a night isn't going to get you in the front door of either of these properties, yet alone get you a pool villa, assuming you're travelling in peak season.
I have been looking at similar properties this week. The Evason has well-priced villas with private pools for around $500 + tax - the normal rooms get criticism on here but the villas seem well liked. Beach is a boat ride away, though. The Sheraton Laguna is cheaper but the clientele in the main building may not be to your liking. The Chedi is cheap enough but doesn't have private pools, I think.