The difference is: on both all Linux distros I know and from as far as I know all BSD derivitives (except PS' BSD) you can compile and use software that doesn't

The difference is: on both all Linux distros I know and from as far as I know all BSD derivitives (except PS' BSD) you can compile and use software that doesn't need to blessed by Tim Apple, be it either through the AppStore or via you forking over money to compile on other Apple hardware with an Apple certified license.