Roller chain offers a consistent rate of travel as the chain passes over a set sprocket size and is stored in the vertical tube of the Sky Hook. Cable on the other hand stacks up on a spool, slightly increasing the amount of force required to lift the load as more of the cable is reeled in. However cable is typically quicker and easier to inspect. Many larger corporations require cable for all internal lifting devices.
Both the roller chain and cable are load rated to meet applicable safety standards. No matter which you choose, you’re sure to end up with a lifting device that will have a smooth and seamless operation.