oh the grey one wasn't released in my country when I got it
seems it has a completely different cooling solution than the Phoenix cards, using only 90mm fans and a 1.5 slot design
seeing as the cheapest Phoenix is only 15 bucks more I'd get that one (if your case can handle the size)
the difference is:
Gainward 1070 (the grey one): 2x90mm fans, 1506/1683MHz (stock speed), 252x112mm, 1.5 slots
Gainward 1070 Phoenix: 2x100mm fans, 1506/1683MHz (stock speed), 285x133mm, 2.5 slots, zero fan modus (fans start spinning at 50°C), backplate
Gainward 1070 Phoenix GS: 2x100mm fans, 1632/1835MHz (factory OC), 285x133mm, 2.5 slots, zero fan modus (fans start spinning at 50°C), backplate
Gainward 1070 Phoenix GLH: 2x100mm fans, 1670/1873MHz (factory SOC), 285x133mm, 2.5 slots, zero fan modus (fans start spinning at 50°C), backplate, more phases than the other phoenix models