I guess it depends on the package to be installed. Anything that can be done
through GPO would be easier to manage but also less risky. Working directly in
the registry is never my first choice. And for the GPO editor, there are
modules that will be able to launch a process that will manage the GPO. And if
you're lucky, there may even be a module to deal directly with GPO. I have to
say that my daily work is on Linux servers, and I use Linux exclusively while
at home. Windows is only a dumb terminal to me.
And I'm far from being an expert in Windows............................. :-(