Sony Artisan Thibault Roland had a chance to interview a top engineer from the A7R II project at Sony. The interview is mostly a rehash of all the features in what appears to be a very good camera from Sony.
What's interesting for Canon shooters, is that Sony is claiming that AF speed with a firmware updated Metabones Mark IV and Canon lenses is almost as quick as a Canon lens on a Canon DSLR.
We were confirmed that AF of Canon lenses was “much faster than before. With adapters (and in particular with a firmware updated Metabones Mark IV) Canon lenses are almost as fast as on a Canon body“. Read the full interview
Keep in mind that “AF speed” is different than “AF accuracy”, and we'll have to wait and see how things work in the real world.
It almost feels like Sony has put some R&D dollars into getting Canon users to want to use the A7R II with their Canon lenses.