Software RAID = simple. At least when I built this machine nearly 10 years ago. Since then it's been rock solid, if not blazing fast. There were also horror stories of hardware raids failing due to controllers failing; or subtle differences between different revisions of RAID controllers. That said I also had budgetary restrictiions at the time that made software raid attractive.

I looked at NAS appliances, but I think it's still cheaper to create one from scratch (assuming existing knowhow, and "free" time :)