I went to gym last weekend. the one in city center ( sofitel hotel). It was not bad. they got gym, open swimming poor (warm water on the top of building), small sauna, shower place...
so I am planing to go there at least once a week. also heard one in crown plaza, it's much cheap than sofitel hotel one. but i don't how is it. have you been there? or do you know any good gym in dubai?