They may not be there for some (maybe most) schools, but there are certainly some having success with them. See http://speirs.org/ for a blog of a guy who seems quite pleased with them at the UK school he teaches at.
I don't disagree with that. Especially in a Private, Christian school for students who are sent there specifically because they want to excel in education.
Though my contrarian side would ask whether full laptops would be more appropriate for such an enviornment
