IPS and Boot Environments using ZFS is an OpenSolaris thing, available in Solaris 11 and some Illumos distributions like OmniOS. And someone has ported BEs to FreeBSD.
But of course, all the cool new features in Linux have been in use in production by Solaris people for years. :-)
See also the Solaris 10 IPS, which appears on the surface to have many similarities (checksums, http delivery of files, etc.) to OStree