Former FreeNAS developer Volker Theille has released OpenMediaVault 1.0, after 5 years of developement. Based on Debian 7, with support for BTRFS and OpenZFS.
http://www.nasstorageserver.com/2014...izec-released/
If you're looking for an easy to use, fast and low-on-resources NAS you may want to have a look at this.