Yeah, I have a GTX 970 and it works great.

I've used both brands.  I had a 660ti upgraded to a r9 390 then decided I wanted to go all out so I returned it and got a 980 ti.  Both the r9 390 and the 980 ti play Ashes great.  At the moment AMD has the advantage due to hardware Async support which is a feature of DX12 that Ashes makes use of.  However Nvidia is supposed to be implementing some sort of work around to get Maxwell to correctly handle Async.

My recommendation would be if you are looking at a 390/970 level card get the 390.  I wouldn't get the 390x or the 980 as their Price/Performance isn't too hot.  If you want to go all out I would go with the 980ti over the Fury X.  

Yestarday i try the R9 fury finaly to test VS my 980 Ti Strix and a normal NV 980 TI

The r9 fury have +/- same performance in some games then NV 980 TI ,but others  the NV980 TI have some more Fps .

My 980 TI Strix in the OC mode win in all tests , specialy on Tomb Raider DX12 (last patch) and on AOTS new Benchmark.

But watever your choice be both very good cards.

Games i test ....NFS 2016/Raise of Tomb Raider /GTA V/Star Wars Battlefront / Batman Arkham/ PLA_Benchmark /Star Swarm/Project cars/Ashes of the singularity.

I try render some projects im working on 3D Studio , Rhino 3d and maya but for some unnow reasons the r9 always crash.

Go for and AMD GPU. Currently AMD outshines Nvidia cards in this game by quite a large margin. Depending on budget, a 390 is probably the best price/performance card on the market.

As others have stated, AMD cards are the better choice for Ashes due to driver...and hardware... related issues that nVidia has with DirectX 12 and Async Shaders. If you are not going to be using DirectX 12 because you are stuck on a non Win10 OS then you want to go nVidia and run the game in DirectX 11.

The decision has many points: power consumption, heat generation, DX11 performance, DX12 performance, and of course price.

Generally speaking, AMD generates more heat, consumes more power, and runs less expensive for similar performance. But this very much depends on exactly which GPUs you are comparing.

If you're after top performance, the R9 Fury cards are beating the 980Ti in many benchmarks. Again, consider the power and heat issues AMD GPUs create.

Lastly, Nvidia will be announcing their next top-of-the-line GPUs which are currently scheduled to be released in June.

My advice?

Set your budget. Figure out what your PC can handle power-wise, how it can handle heat, then consult many benchmarks for settings and games YOU would use. Last is price shop.

Good luck!