If you haven’t gotten a chance to check out Michael Lucas and Allan Jude’s book on ZFS, FreeBSD Mastery – ZFS, userhas written a review which may help you out with that decision.
Once again a great FreeBSD book to read. I was anxious to read this after reading FreeBSD Mastery- Storage Essentials 2014. I read where he was writing a ZFS book, but didn’t know it was out until I was asked to review it. I loved the introduction, being into hardware and history, it was such great knowledge. I knew some of this information prior, no where near as in depth as these authors covered. The style is so easy to read and mentally kind, it’s always a pleasure to read. Of course ZFS has been used in other Oses (such as Solaris and Linux) and while it is not new to FreeBSD, many people are either afraid of it because they are moving from Linux or they have heard negative things about it.
Check out her full review here: http://www.cyberciti.biz/datacenter/book-review-freebsd-mastery-zfs/
You can purchase the book from Amazon: http://www.amazon.com/FreeBSD-Mastery-ZFS-7/dp/0692452354/ref=sr_1_1?ie=UTF8&qid=1446866943&sr=8-1&