Monte Carlo perturbation analysis has progressed considerably during recent years. Generalized schemes for correlated tracking and higher order derivative operator sampling have been elaborated for commonly used estimators. For special problems, like voiding of strongly absorbing regions, new solutions have been developed. Their respective advantages, especially in view of variance considerations, have been analyzed for simple models. Also, perturbations of eigenvalues could be determined by these methods, provided the usual source iteration procedure is coupled with adjoint weighting or replaced by the Green's function (fission matrix) approach.