When paver steps require some repair, it is easy to simply replace the individual paver or pavers in question. With concrete, damaged sections can be fixed by patching them with new, wet concrete. As to which of the two is easiest, it really depends on how the pavers are installed.
Ease of Repair
Paver steps that have been mortared into place are harder to repair than loosely- or tightly-packed steps. Mortared steps require that you break through the mortar surrounding it, replace the step and re-mortar a new step in its place. Packed steps can be removed and replaced. Concrete repair requires patching the damaged section. That's harder than replacing a broken paver, but probably easier than replacing a broken mortared-in paver.