I'd go Fury over a 980. Seems to be around 10% faster on average at that res, remember also that Fiji just came out so I'd say drivers over the next few months will improve performance even more vs Maxwell that has been around for 8 months or so now.
Make sure you look at OC vs OC if you're into overclocking. 980 OC's like crazy (ran mine at 1550, a ~30% OC) where Fury's OC is negligible from what I've seen. A stock 980 traded blow with a 290x but OC vs OC it was ~24% faster according to the [H] review.
Honestly though - neither card is enough of an improvement from a 290x IMO.
If you really value other factors, such as maybe quality of life improvements (noise), you'll have to decide how much that stuff is worth it to you.
From a pure performance stand point though you are getting very little for the $500+ or $550+ costs.
If you don't really care about the monetary aspect (which is fair enough, a lot of people on here don't) then you might as well move up higher and get a 980ti.
The odd thing about this generation is the high end GTX 980ti actually offers better value for the dollar than the lower cards below its segment. Whereas typically you've had massive diminishing returns as you moved up in price range.