So got my Money back on my 7990 after gigabyte sent another faulty card. 
Using 570 2.5GB
Budget 750-800 pounds
Resolution 2560x1080 (for now might get 4K next year)
I'm thinking
2x 290X
2x 980 (Depending on reviews)
2x 780 6GB
2x 780TI
or
1x Titan Black now & 1 later?
Only thing leaning me towards nvidia is Witcher 3 support
however other than PhysX not sure what Nvidia Offers over AMD on witcher 3
for example
Hairworks - AMD support?
The other effects open for AMD to use or Tied down? or less optimized

Using 570 2.5GB

Budget 750-800 pounds
Resolution 2560x1080 (for now might get 4K next year)
I'm thinking
2x 290X
2x 980 (Depending on reviews)
2x 780 6GB
2x 780TI
or
1x Titan Black now & 1 later?
Only thing leaning me towards nvidia is Witcher 3 support
however other than PhysX not sure what Nvidia Offers over AMD on witcher 3
for example
Hairworks - AMD support?
The other effects open for AMD to use or Tied down? or less optimized

), epic value atm 