As you can guess from the title, I've made a benchmark list for Equihash. I've gathered info from bitcointalk and the Zcash/Zclassic chats/forums. The list is not yet complete (it will most likely never be since the miners get updated so often and plenty of new cards are coming up this year).
Much of the data is being hard to get without first hand experience but I managed to gather some, this is the list at the moment:
https://zdeveloper.org/wiki:zcash_mining_benchmarks I'm waiting for corrections and updates. Maybe it will helps some people decide which cards to get next time they assemble a rig.

Most power efficient (Sol/Joule) cards:
AMD RX480 Sapphire Nitro+ OC 8GB 305/140 = 2.2
NVIDIA GTX 1070 - 8GB 450/100 = 4.5
Shockingly, Nvidia is more than twice as efficient...
1070 is also about twice the price.