I could see them doing well if 350 or less.
That's pretty much my sweet spot. Under $350 shipped is an insta-buy.There is an argument that 2 of them are as good as a 1080ti.
I just sold the only 2 I ever had of them I am pretty much all nvida at the moment.
Pros against a 1080ti:
Will do ~58MHs ETH (hot!)
Will do ~1600 cryptonight (hot!)
Less than 200w (not hot!)
No nVidia algo is super profitable atm
Cons vs 1080ti:
2x more risers
2x more slots
2x more cables
2x the licenses
2x the potential issues
2x the vbios flashing
...but all the above at 3/4 of the price of a 1080Ti currently.
This being said, it's still very hard to find any under $350 (At least here in Europe - you might be luckier across the pond).