I stayed there for a week in September 2007. The pool, grounds, public areas, facilities and food were good. The room was dated (80's decor) and not up to Starwood scratch. The distance to town was a bit annoying although there was a shuttle bus so the inconvenience was not huge.
That said, I am about to go to Port Douglas again in August and have decided against staying at the Mirage. We've opted to stay in a self catering apartment in town.