This is a very subjective question IMO, because having a lazy so and so home-schooled by parents who don't give a **** just wouldn't work. Also, I believe some level of public school attendance is required at some point just so you can make a few friends and become social, although as far as education is concerned home-schooling is IMO the best option... but only if both the student(s) and the parents are willing to put time into it.
It completely depends on the student and teacher. If a child has special needs and is really dependent on one to one help, then home schooling would seem like the best option. However, the parent needs to be able to give the child an appropriate standard of education. If the parent is a bit dull and generally doesn't have a clue, it's not going to work out all that well.
If we are talking your average C grade student, then I think that public education is the way to go. Although the student potentially has the opportunity to get higher grades the loss of the social aspect of school could really harm their development. Employers aren't all that worried about your qualifications. Sure they play a part but it's not the be all and end all. The student needs to learn the social skills that will allow them to work as part of a team when they get to the workplace. Let's be honest, most children are socially retarded.