For a simple RAID-1 setup, ZFS is sort of overkill. It looks like you're using a home fileserver with only one user, in this case performance probably won't increase either.
Here is an overview of ZFS features, go through the list and see if you really need any of them:
http://en.wikipedia.org/wiki/ZFS#Features
Personally, I haven't yet found a use for ZFS ... I do know Phoenix uses it for backups at work, he described the setup and the advantages somewhere ... Either on this forum or on the FreeBSD Forums ... (Use search).
However, using ZFS might prove educational or fun. Altough I would be careful to have a backup of my data, filesystems is not an area where you want to make mistakes ...