ZFS vs others
ZFS is now available on different OS families with their own history and a separate development.
The Solaris familiy (Oracle Solaris and OpenSource forks )
This is where and for what ZFS was developed. The ZFS integration and performance with in Solaris and the kernel embedded NFS and multithreaded SMB services instead of the usual SAMBA SMB server (that is also available) is unique. This and the Comstar FC/iSCSI blockbased service with Crossbow, the network virtualisation stack in Solaris is the perfect base of a minimalistic ZFS Storage Server that just works out of the box. Due the OpenSource options based on Illumos, this option is more and more considerable outside the enterprise area. Solaris is best supported on serverclass hardware.
The BSD Family (another Unix option)
ZFS is available and supported on BSD for many years. Regarding services example SMB, BSD is using SAMBA. BSD supports a wider range of hardware than Solaris and there are many well documented software projects outsice the storage area like mediaservices or firewalls.
The Linux family (a unixoid option)
The maxim is, you can do anything on any hardware and it there are always many alternatives for each problem where you can choose one or another. ZFS and storage is an option among many others. It lacks the integration, simplicity or the "It just works" experience of a Solaris ZFS Storage server. Main advantage is the availability of a wide range of OpenSource projects and the best hardware support especially on non mainstream hardware.
For some time, OSX server comes with a prerelease of ZFS but then Apple decded to abandon professional storage and ZFS.
Now ZFS is an option for OSX under the roof of Open-ZFS. The impact is minimal.
About highend filesystems
Compare btrfs, ReFS and NetApp WAFL vs ZFS.
These four filesystem are widely used top-end filesystems
Google: ZFS vs btrfs
Google: ZFS vs ReFS
Google: ZFS vs NetApp WAFL
ZFS vs older filesystems
Google: ZFS vs ext4
Google: ZFS vs ntfs
Google: ZFS vs HFS
Prüfsummen und CopyOnWrite, the essentials of ZFS
Google: What is CopyOnWrite
Google: Why checksum is needed
ZFS Raid vs HardwareRaid/ Raid-5/6 Raid
Google: ZFS Software-Raid vs Hardware-Raid
Google: ZFS Raid vs Raid5/6 Writehole problem
Solaris vs NetApp or LInux
Google: Solaris ZFS vs FreeNAS
Google: Solaris ZFS vs Linux
Google: Solaris vs NetApp
Different CloswedSource/ OpenSource options
While the main platform of napp-it is currently OmniOS Most or all features are available on OpenIndiana
and Oracle Solaris (fully supported). Linux is supported with replication and ZFS management.