There seem to be two definitions of what a saturated class should be: 1. A class of morphisms closed under retracts, pushouts and transfinite composition. 2. A class of monomorphisms containing all isomomorphisms, closed under retracts, pushouts, arbitrary coproducts and countable composition. My question is, does it make a difference which definition one choses in the context of the cofibrantly generated modelstructures on * $\mathbf{Top}$, with respect to the Quillen model structure * $\mathbf{sSet}$, with respect to the Quillen (or Kan) Model structure * $\mathbf{Cat}$, with respect to the Thomason model structure