The new lens is finally in Stock for the first time via BHphoto, Amazon, Adorama, FocusCamera. In EU at Park UK.
Dpreview published the full Sigma 150-600mm review and concluded:
Overall, we find the Sigma 100-400mm F5-6.3 to be a compelling offering. Ergonomically it’s great, in large part thanks to its clever zoom torque control and the push-pull zooming it allows. It’s also a very sharp lens that’s really not as bulky or expensive as you might expect for its focal range and maximum aperture.