The accuracy of the phase space time evolution method applied to neutron transport is contrasted with a one-dimensional discrete ordinates code with anisotropic scattering, ANISN, a time-dependent explicit discrete ordinates code, TIMEX, and theoretical benchmark values for critical bare slabs. The comparison is performed by calculating the critical value of v (the number of neutrons released per fission) for slabs of various halfwidths. Furthermore, pointwise flux differences are displayed for one particular slab thickness. Finally, a nonlinear time-dependent problem previously solved only in diffusion theory is considered.