It's faster than a 980 across the board, especially once you move beyond 1080p, and absolutely blows it away in DX12/Vulkan titles (indeed it can hang with a 980 Ti/1070), so a lot more futureproof for someone looking for a card for the next couple of years. I don't see any reason why you'd consider a 980 over it. The Fury cards will age much, much better than the 980 over the next few years, with the new APIs becoming the norm.
The 980 Ti is more arguable, but I wouldn't touch one of those either at this point, personally. Having recently ditched a 780, I know how it goes with old Nvidia cards and a lack of driver support. The only options I'd consider are the Fury at £300 or one of the many decent 1070s that you can get for just under £400, because that's a card with a much brighter future than the 980 Ti.
Not necessarily driver improvements, but the availability of more DX12/Vulkan titles, where the Fury cards start to shine.
Of course, you can knock 5% off those numbers for a stock non-X Fury. Certainly the choice is clear between it and the 980, and as I said I firmly believe the 1070 is worth the extra money over the 980 Ti. So it's really a matter of whether you have £300 or £400 to spend.