Have just come back from Port Douglas. Stayed in a villa at Sheraton Mirage, and it was great, a walk across lawn to the beach, plus hotel has some great "lagoons" for swimming.
Breakfast was included, and buffet selection excellent.
Staff were friendly, tour office and reception very helpful.
Refurbishment is planned for the hotel, but surprisingly it is holding up quite well for its age. Rooms look adequate from looking at them, though maybe not as spacious as the villas.
The really big benefit of staying at the Mirage is the extensive grounds, well maintained and expansive.
I've heard good reports of the Radisson, but you don't get anything like the same environment.