Charter schools are about as good on average as public schools. But because they can fail, they provide opportunity for improvement that public schools don't. Without failure, it's much harder to generate improvement.
The Freakonomics podcast recently featured this telling analogy: What if restaurants were run like public schools? Imagine if you were required to dine at your local government-run canteen, with dishes determined by a citywide restaurant Superintendent, with a no-firing policy for staff?
Sounds like a bad Yakov Smirnoff joke. "In Soviet Russia, restaurant eats you!". We instinctively realize that restaurants like Gramercy Tavern should succeed, while Joe's Yak Butter Hut should go out of business. Failure ensures survival of the tastiest.
Yet while few would support the idea of a restaurant Superintendent, we allow the same crazy system to educate our children.
I guess we consider our seared ahi salad more important than the future of our country.