Kangaroo Carrier Has Anyone Tried Both The Baby Bjorn And Kelty Kangaroo?

Has anyone tried both the baby bjorn and kelty kangaroo? - kangaroo carrier

Looking to buy a Kelty carrier, or a kangaroo or wallaby. I wonder whether they support the children and the Bjorns and how they are used to support the back. I tried to compare the original Bjorn, Kelty, but how?

Thank you.