I've never stayed at Rizo de Oro, but I have buddies who swear by it and others who stay there when Cascadas is full. Tropical Bar has gone downhill, so I almost never take girls from there. But as you said, HK girls can go to Rizo (and Tropical girls can go to Cascadas).
But if I'm staying at Cascadas it's almost always Mon or Tues, and at 80% off I might as well get a Master Suite. So I don't bother with Rizo.