I looked at it in IRIS and it has about the same read noise as all the production camera ISO100 blackframes I've seen (which are all a trace worse than all of the pre-pro black frames actually). Same noise, no horizontal banding, but still one of the vertical banding types. There is a chance it MIGHT be possible to design a pre-RAW processor to filter out this type of vertical banding, not quite sure yet, possibly though.
The random, non-pattern read noise itself (ignoring banding) is just like with the 5D2, no better at all.