For me, choosing the K8NS Pro lies on how much ATA devices you want to attach to the board. It offers more ATA-based flexibility than the ASUS K8N-E, keeping almost every other comparable feature the same, so if SATA isn't really your bag yet (and why should it be if you have a nice investment in big ATA disks and maybe a couple of optical burners), the K8NS Pro is a fine mainboard.