Correct me if I'm wrong (please!) but FreeNAS still can't (easily?) do what Synology's 'Hybrid RAID' (basically sharded RAID across drives) facilitates; growing your (redundant, e.g. 1 or more parity drives) volume by adding more drives, and also growing your volume by replacing drives with larger ones.
I've always thought that was essential, it bemuses me that there aren't many solutions out there that help you do this. I guess everyone must buy have loads of disposable income to buy 8 drives at once.
I'm not sure about FreeNAS, but I do want to point out this is possible in the btrfs filesystem (sharded raid across drives). I'm not aware of any FreeNAS equivalents though utilizing it, but rolling your own is certainly an option.
I've always thought that was essential, it bemuses me that there aren't many solutions out there that help you do this. I guess everyone must buy have loads of disposable income to buy 8 drives at once.