A new video surfaced over the web, you can clearly see adapter taken from a box with Metabones logo / brand name easily fitted over Canon EOS M mirrorless camera, the AF is working smoothly and Max available aperture is F2.0.
About Metabone Speedbooster – Mounted between a mirrorless camera and a SLR lens, Speed Booster increases maximum aperture by 1 stop (hence its name), increases MTF and makes lens wider by a factor of 0.71x. Optics designed by Caldwell Photographic in the USA (patent pending).
I hope that the fps is higher than 10 and the autofocus is fast like 0.05 and it has 18 mp or higher