  We perform a detailed analysis of the properties of stationary observers
located on the equatorial plane of the ergosphere in a Kerr spacetime,
including light-surfaces. This study highlights crucial differences between
black hole and the super-spinner sources. In the case of Kerr naked
singularities, the results allow us to distinguish between "weak" and "strong"
singularities, corresponding to spin values close to or distant from the
limiting case of extreme black holes, respectively. We derive important
limiting angular frequencies for naked singularities. We especially study very
weak singularities as resulting from the spin variation of black holes. We also
explore the main properties of zero angular momentum observers for different
classes of black hole and naked singularity spacetimes.
