I bought a 4 port SATA PCI controller for about $25 and let SME setup a 4 disk software RAID5 array. It has been working great, except for when I hosed GRUB...
Software RAID setup in SME is painless, especially if it is a fresh install. The installer sees how many drives you have and then sets you up for: ready for RAID1, RAID1, RAID5, or RAID6. I personally didn't see the value in trying to get hardware RAID configured, it might be simple as well, but software RAID works "out of the box".
Ryan