Review on FreeNAS by Dre Fishburne

I like that it's free, has great community support, easy setup for new users. It does not have native GUI for setting up RAID arrays but you can do so with command line tools. If you are looking to build your own NAS then FreeNAS will be good fit as its very stable software (it hasn't changed much in years). We use FreeNAS at work and it works well. Our only issue was we needed more space when building our file server. But this could also be because of other services being installed on same machine. We were able to create some additional partitions for extra files/data without any issues.