Here is one user's report of the performance:
* Noise now has a lovely film like fine grain, much more organic and less electronic looking
* Noise smears far less detail
* Low light performance is just better all round
* Less compression appears to have helped with banding on gradated tones, looks closer to 10bit than 8bit!
* Significantly better than the high bitrate MJPEG mode especially in low light
* Colour seems improved, I am getting some beautifully rich tones out of it
* Detail has increased and is much more solid looking, even with heavy camera movement