Proper file locking, asynchronous operations across everything, ACL based security, proper ABI.

Not being an OS from C to C as the main programming model.

And then on top, multiple levels of sandboxing, including virtualization of drivers and kernel modules.

Ah and RDP is much nicer than X Windows or VNC.

Other than possibly proper ABI, and yes a tiny handful of file operations that could theoretically block not available through io_uring, like ioctl and splice, Linux has the rest.

In security? Not really, unless you are doing immutable deployments with rootless containers, no shell access, which at the end of the day isn't UNIX any longer.

And which Linux exactly? Plus unless you're doing C or C++, most likely aren't using those APIs.

Anyway, the differences of bare metal servers don't matter in the days of cloud where the actual nature of the kernel running alongside a type 1 hypervisor hardly matters to userspace.