GTX 1060 or R9 390x?

Hey all, looking for some advice on a new GPU..., currently looking at either a 390x or a 1060.

I know the 390x is essentially just an overclocked 290x but is cheaper than a 1060 and from what I can tell is similar (?) in speed, but they are becoming harder to find...

But then the 1060 is brand new technology and will likely have a longer supported life than a 390x but is more expensive...

I'm looking to get one so I can play GTAV, Just Cause 3, Witcher 3 etc. on Ultra (or if not very close to). I only have 1080p monitors so not really looking for 4k or VR support.

Thoughts? Any other cards I should be looking at?