I was thinking of Filesystem you can install your operating system to.
And from what you can boot multiple different operating systems,
and using same boot/system disk(s) together with shared data disk(s) pools.
ZFS, being supported for boot from Illumos,Linux and FreeBSD is the best system I know for the moment i you want to be free of OS/Platform constraints or even architecture constraints (same ZFS pool works on SPARC and x86 without changes)
I do not believe Btrfs for stability and production use for now.
If I tend to be supported with Linux install I would go with ext4 for system disks (I think ext4 now has snapshots)
and ZFS for data pool that applications actually use to work with or store data to.