To be fair, the 290X and 280X will be judged solely by DX11 at launch. If Mantle changes that, great, but that's a few months away. I think it has a lot of potential, but i'm leery of declaring any card a winner based on Mantle - most folks want benchmarks and we won't have that for a long time.
What is annoying are the suggestions that the 290X will cost 700$+. Seeing as the card will (as it should) be judged by DX11 benchmarks (including BF4) upon release, I highly doubt anyone will pay 700$ for that card when they can simply buy a pre-overclocked GTX 780 instead. AMD has always been pretty good with the value cards, but on the high end I would like to see them put a meaningful fight up. And they can do that at 550-600$ with the 290X. At 700$+? They are completely throwing their opportunity away. I don't think anyone will be interested in that when they could simply buy an overclocked 780 which already matches the Titan out of the box.'
Heck, even the best pre-OC'ed 780s are under the 700$ mark. I think if AMD launches the 290X at 700$, a large percentage of potential buyers who WOULD bite at 550-600$ would otherwise simply laugh and shrug their shoulders at the 700$ price. I hope AMD isn't stupid enough to release it with that kind of price premium......I've said it before but AMD doesn't have the brand loyalty (as NV does), yet, to get away with price premiums.
The BF4 tie in with the AMD brand is great. But, like I said, nobody will judge bf4 / 290X by mantle for a long time and will instead look at DX11 initially. With that being the case AMD needs to play their cards correctly and price the 290X properly.