The perpendicular magnetic anisotropy of both amorphous Tb-Fe and crystalline fcc Pt-rich Co-Pt alloys is enhanced by increasing growth temperature, up to the onset of significant bulk atomic mobility (approximately one third of the melting temperature). High growth temperature also stabilizes these materials against subsequent annealing which tends to eliminate the anisotropy. The dependence on growth temperature can be fit with a two-level systems analysis in which the low energy surface state during growth is anisotropic. The source of this low energy state is suggested to be related to surface segregation for the Co-Pt alloys. The anisotropy for both materials shows very little dependence on substrate type, sample thickness, or details of the deposition such as sputtering or e-beam evaporation. Coercivity on the other hand is extremely dependent on microstructure and hence on details of preparation, substrate type, thickness, and crystallographic orientation. For α-Tb-Fe, the dominant mechanism appears to be domain wall pinning by microstructural defects in the bulk of the film, such as columnar microstructure.