I'd wait to published reviews from reputable sites arrive containing reviews of aftermarket cards ... Here the 970 wins more than it loses:
http://www.anandtech.com/show/10446/the-amd-radeon-rx-480-preview/4
On the other hand, TPU has the 480 bettering the 970 by 6% (1440p) in their test suite. Nothing new here, the R9 x80 has essentially been the only AMD horse in the race for the last 2 generations.
https://tpucdn.com/reviews/AMD/RX_480/images/perfrel_2560_1440.png
Remember though, since the introduction of the 2xx series, AMds cards have consistently had limited OC ability, resulting in just single digit FPS increases. The 9xx series sees OC'd fps increases from 17% to 31% ... the 3xx series 5 to 8%
TPU tested the 970s overclocking ability at 17%
TPU tested the 480s overclocking ability at 5%
Doing the math....
970 = 94% x 1.17 = 110%
480 = 100% x 1.05 = 105%
We'll have to see if non-reference 480 cards can improve on that.
AMD released the 480 first for a reason ... well I think multiple reasons
1. They can ill afford repeats on the 7xx and 9xx series where AMD invested in huge marketing campaigns for theirir x80 topplers only to have nVidia drop the Tis right on their heels.
2. AMD is a long way from anything that compete with the 1070 and 1080.
3. The 970 outsold all AMD 2xx and 3xx card cards combined by a factor > 2:1.
So the 970 has to be their first punch and, it would appear that they made a pretty good offering. At $199 ... say $219 - $229 for the non-reference ones, that is quite a "shot across the bow" at the 970.... however, we already saw 970s as low as $239.
If AMD can pick up another 5% OC on the non-reference cards ... and can maintain a price advantage after nVidia slashes prices, then they have a competitor on their hands.
OTOH, nVidia has slated the release of the 1060 for 3rd quarter (along with 950 and 940) ... which is 2 days away. So we can expect to see that card drop into the channel in the next 2 - 92 days. The 280 and 380 were AMDs most viable cards against nVidia competition, the problem was anyone considering a 380 vs a 960 couldn't help but be pulled by the performance price of the jumping to the 970, which arrived on the scene well below the $400 price range for the x70 series.
So yes, the 480 has the same appeal that the 280 / 380 did only now we don't know what the 1060 looks like. I'll make these forecasts:
1. The 970 will see price drops in the next week or so.
2. If the 970 is competitive , we'll see it soon.
3. This is pure conjecture but nVidia knows that the 280 and 380 were the better cards against what they had to offer in this niche. Ya gotta think that with the x70, x80 and x80Ti series being a slam dunk, they spent some time in the last 8 months figuring out how they can improve the position in the GTX x60 vs R9 x80 segment. So I think they will have a better showing here than in the last 2 generations. We'll know soon.