gtx 1060 and 1070 are good enough for cryptonight.
GDDR5X based cards are a no go, instead; talking about 1080 and bigger.
I have tried my 1060, 1070, 1070Ti, 1080, and 1080Ti cards on Cryptonight -- just didn't seem worth it vs. doing something else.
Even a 1080Ti doesn't best an RX580 by much.
The 1060, 1070, 1070Ti beat both the 1080 flavors in value, of course, with standard GDDR5... but in my analysis AMD still rules Cryptonight.
So I have all my AMD RX560, RX480, RX580, RX570, old school Radeon 78xx 79xx, RX VEGAs, and CPUs on Cryptonight & nVidia GPUs on a profit switching pool (ZPOOL right now).
I picked up more RX580s & 570s specifically to mine ITNS =)