I am a member at Pure Fitness Asia Square and totally recommend it if you are looking for a large gym with low density membership. I've never had to wait around for machines and can always find a spot to do core conditioning. The higher membership price is worth it.
Was at Pure Fitness Knightsbridge and it's much more crowded.
However, if you like Muay Thai, note that Pure Fitness Asia Square doesn't offer that on a group class level as they are trying to promote their Muay Thai PT at the ring there.