For 6 RX 570's you should be getting ~170MH/s. - I'm currently getting ~28.35 MH/s dual mining on the single RX 570 I have.

Long and short answer is, are you holding or selling? Selling right now, might be worth profit switching. However if you are holding, then... best guess is (and what I'm doing) is continue mining ETH - I'm using 8 RX 580's right now for it.