Two 1060's will have a better hash rate than one 1070 or one RX 580, except when dual mining. TDP on 1060's is good as well <100 W. If you can get two 1060's for the price of one 1070 or one RX 580, then get that.
Im think about DAG for 6Gig. somone says 6Gig is worst is he right?
Thanks