I rarely check Hyatt's or Hilton's websites anymore, especially Hilton, as they rarely list their lowest available rate. I've consistently found http://www.travelweb.com to offer the best available rate at most properties. Both the $69 rates you quoted are there, by the way, but the Hilton's is non-refundable.

In my experience Travelweb ALWAYS lists lower rates than either Sheraton or Westin's websites.

You know, with rates that low, you could probably get a 3* through Priceline for half that price or even less with bonus money.