Linus Torvalds called ZFS one of the very few bright spots in Solaris. ZFS released under Sun's Common Development and Distribution License. Linux is under GPL v2 which makes ZFS incompatible with Linux. I’ve used ZFS under Solaris and it is absolutely rocking file system.
Now this hot feature from OpenSolaris is taking a weird but working path to Linux inclusion using FUSE (Filesystem in Userspace).
If you like Linux for the long list of supported hardware but Solaris for the advanced new ZFS filesystem, a new development project might have a happy surprise for you. One advantage to putting ZFS into a separate daemon is the same as something that microkernel operating system developers have been talking up for years: You can kill and restart the filesystem independently of the operating system.