Best GPUs for RVN mining?

I am currently using 470 4gb cards and want to invest in some more cards.

I looked through the Links and didnt see any GPU recommendations so i figured id ask some veterans! I want to build another 4gb rig as well as a more powerful rig in consideration of hashing power wattage and overclocking potential.

I'm wondering what other GPUs dominate in RVN. I know all GPUs can mine RVN, but im wondering what are the most common ones used

Thanks all in advance!