Please see our response to a similar question below. Hope that helps. Thanks.

"The main difference is that Sysbox is OCI-based, so it works with Docker/containerd and hopefully K8s soon (we are working on the latter). Also, correct me if I am wrong, but I don't believe LXD runs K8s inside without privileged containers. Having said this, I know LXD and Sysbox use many of the same OS-virtualization techniques to do what they do. And in fact we owe much of the work we've done to the ground-work done by the good folks at Canonical/LXD."