While unschooling is great for some kids, I agree with others that this is mainly a good practice for some young kids. When kids are young, it is tough to see that what works now - be it in academics, sports, music, etc., - may not work when kids are older. I was just looking at a sports forum and a proud father had posted a "skills video" of his daughter. She looked pretty good for a 12 year old, but there were clearly issues with some of her fundamental skills. She can get away with that lack of proper form/skills at this age, but later on it will bite her in the behind. I think it can be much the same with unschooling.
I also think the possibility of unschooling older kids varies from country to country. I think that unschooling HS age kids in the US is not a good idea - that is, if the kids want to go to college. I did a search on unschooled kids going to college (in the US), and most unschooling parents had joined some sort of group that could provide a transcript for their kid. So, while much of the experience might have been unschooling, to be a qualified applicant for a sort of decent school in the US, I don't think these kids were purely unschooled.
In countries where HS graduation and college entrance depends upon a national exam (and not much else), the unschooling approach may work. Ace the exam and attend the college of your choice.
With my eldest, unschooling would have been a disaster. She has her areas of interest and would have avoided everything else. Heck, she tried to do that to some degree even in regular school. Middle kid is more self motivated and quite even in her abilities (across all subjects), so it might have worked when she was younger. Youngest has asked about homeschooling from time to time, but she is fine in school and likes the social aspect.
