Come on people, you were expecting it to be cheap? Less than 10 years ago I paid over £60 for a 512mb USB stick which was considered ludicrously big. Only a few years ago a 16GB stick was well over £100. Current tech is cheap because economy of scale has won out.
As for how fast? The article says 125MB/s. Current comparable technology is the 90MBs CF card:
http://www.amazon.co.uk/Sandisk-Extreme-Compact-Flash-90MBS/dp/B002OP5UCM/ref=sr_1_4?ie=UTF8&qid=1325928368&sr=8-4This isn't designed for consumer cameras, this is aimed at HD video and medium format SLRs. The write speed of SD makes things like 4K home video impractical. And up to 600MB/s? That's insanely fast, but the RED Epic needs up to 225MB/s for 120fps 5K footage so you can see how this is useful.
Nikon seem to be on board already and it's camera makers that will ultimately decide the fate of this, I think. Sony will presumably also roll this out to their cameras - remember they're very big players in prosumer video (they work with a lot of big TV companies, including the BBC) as well as their compacts, SLRs and maybe even other products.
Note that it was developed by Nikon, Sony and Sandisk so hopefully we're not going to get a Canon-Nikon format war…