I'm very leery of Canon's ISO figures, they are for jpeg images that are highly processed with lots of NR. Their Digic 5+ gives them power to do a lot of good quality NR, but it does not boost the underlying sensor performance. Still, any improvement is good. They claim ISO 12800 (25600 expanded) which is definitely a stop better, but its for jpegs.
The native ISO of a RAW image is more telling.
I hope it has AFMA, without it, images using a 20mp sensor will not be as sharp as they can be.