We illustrate the utility of the "mean-field" rate equation treatment of nucleation and growth with critical size i greater-than-or-equal-to 1 for both isotropic and strongly anisotropic diffusion. Some comparison is made of rate equation predictions for mean densities and size distributions of stable islands with predictions from "exact" simulations for the low coverage precoalescence regime. We also consider island separation distributions, depletion effects, and associated splitting of kinematic diffraction profiles. We necessarily treat other issues via simulations. These include analysis of (i) transitions in island shape from compact to dendritic, as observed for Pt/Pt(111), and extraction of associated edge diffusion barriers; and (ii) adlayer percolation, which sometimes mediates the population of higher layers. We also briefly comment on nucleation and growth behavior in the specific systems M/M(100) with M=Fe, Pd, Au, Cu, Ni, and Ag.