I'm looking for a recommendation on which card to purchase:

Sapphire Pulse RX 570 4GB
Asus Strix RX 570 4GB
Asus Dual RX 480 4GB

The prices for these cards are all the same, but I could get the Strix soonest.  I will be primarily mining ethash, likely dual mining.

Thanks.

Edit: corrected 470 to 570, as these are my current options.