the staff are great, and there is plenty of cardio machines. however if your joining for classes think again, they are often over crowded and other members can be rude and push you out of the way for a place in one, I've seen several people walk out because there simply wasn't enough space or equipment to go around.
Cardio heaven! So many elliptical trainers, treadmills, stationary bikes, rowers, etc, that even at lunchtimes and other busy times, you'll probably still be able to get a machine. Also boasts good views over Darling Harbour, and the high-glass windows and corner location make for a very open-feeling gym. Recommended.