(imported comment written by gjeremia91)
the relevance I provided looks at ALL the users, i.e. gives you the default for all users. HKCU registry key is really a mapping of the presently logged in HKU<user> tree. That can be obtained a few ways. One easy way is: ‘component string of sid of current user’
So comes down to, do you want to know the default priter drivers for all users, or jsut the currently logged in user?
What about systems where the user is not logged in?