If you use a card, yes, you can migrate more easily. I have personally found that I can swap RAID sets between my 2 SiI cards (3114 and 3132). However there can be a massive performance penalty (depending on the speed of your drives unless you spend big bucks on the RAID system. My PCIE x1 RAID card is limited around 140MB read but the drives can reach that on thier own. PCI is also limited quite heavily. But If you Raiding older drives this might not matter.