That is a good question and one that I think many people may not understand. Charter schools are publicly funded schools (i.e. they are not private), but they often have more loose curriculum standards and are more experimental than your regular public school. Here is a collection of information that might help answer your question further:
my son is 15 years old and he goes to a charter school
hes been going for 2 years now and i love the academics and i love the settings.
the thing is public schools have way to many children in one class and a child gets left behind i find that charter school although is publicaly funded is better for my childs learning.
when he was in elementary they just pushed him along even when he didnt know the work and didnt do there best to help my son.
i also think that parents need to read into charter schools more before assuming the wrongfulness that it is being displayed