I went to an OpenSolaris users group last year. They were talking about new network features like being able to assign sub-interfaces to different zones. Stuff that VMware ESX had available for years. I was thoroughly unimpressed. The concept of Zones or FreeBSD jails has some appealing aspects; not needing to load multiple kernels in memory, for example, but by this time, Hypervisors such as VMware that deduplicate memory blocks pretty much negate any advantage Zones/Jails once had.

ZFS definitely has some potential though. I hope it will be released under a more liberal license that will allow a direct Linux kernel module as opposed to fuse support.