That was incredibly interesting, thank you. The use of only a single color sample and many coverage samples together with neighborhood information to reconstruct edges is awesome. And I had never seen the FLIPQUAD sampling pattern before.
I think it's just a bit slower than FXAA which I remember being from around 0.8 to something like 1.3ms in 1080p, but that's just what I remember out of the top of my head. But in any case the difference shouldn't be huge so if it works well and they end up releasing the whole codebase then I could see this becoming popular which would great as most games in the future will use a Post Processing AA technique due to the rise of deferred renderers.
I'm loving the advancements of post-processing antialiasing. There shouldn't be an excuse for a game to release with zero AA these days, especially with decently efficient post-processing methods being so cheap.
I've found that between SMAA and TXAA, SMAA is the better option. It can be used regardless of your gfx card and it doesn't have the same performance hit that TXAA does while providing a similar level of AA.
One problem I see here is NVIDIA's drop of support for CSAA in Maxwell and beyond. This AA seems to be based on CS access from shaders which a) only GCN provides right now it seems and b) is completely missing in Maxwell+ alongside CSAA itself.