Yes Rich but that Raidlike means that you still have the same specs as a standard raid.
Look at the drive configurator on the link you posted. Put in two 500G drives check the outcome and then put in a 350G and a 500G drive and check the outcome again. Thats the same as a Raid 1 config.
The one disk data redundancy is just the software partitioning one disk in two and sets these partitions in a Raid1. If the disk then breaks/crashes there will be no data left.
It is great that they build a box and wrote some software that configures the raid for you but i think for me it’s a bit on the pricy side for me. With a raid 6 controller you can build a cheaper and an even as good system. And yes it’s not easy but it’s a real nice challenge 🙂
And also good to keep in mind that there is no swapping disks for reasons other than that they are broken in any raid or beyondraid system.