  Harmonic oscillator coherent states are well known to be the analogue of
classical states. On the other hand, nonlinear and generalised coherent states
may possess nonclassical properties. In this article, we study the nonclassical
behaviour of nonlinear coherent states for generalised classes of models
corresponding to the generalised ladder operators. A comparative analysis among
them indicates that the models with quadratic spectrum are more nonclassical
than the others. Our central result is further underpinned by the comparison of
the degree of nonclassicality of squeezed states of the corresponding models.
