With luck, BIOS modding and overclocking you can potentially achieve 28 MH/s at a very nice power consumption wattage.
These facts are the only ones that matter, and won't change with any AIB RX 570 you get.
28MH/s? I have RX 470 with more than 30MH/s.
I assume you get that with highly tweaked timings? I was only referring to simple, heavy-handed strap copying.
What's your power consumption?