Agreed - it depends on what you're trying to do. However, if you make changes as the local Administrator on your build, and then set CopyProfile to True in your unattend after you run sysprep to generalize/prep your install image, that Administrator's profile gets copied to the default user's profile when the image is applied (most settings, not all, but close). See
this blog post from the Deployment Guys on your options, supported and otherwise.