I think people confuse charter schools with magnet schools.
My daughter attends a magnet school and it has it's pluses and minuses.
Pluses, wonderful instructors, that are well paid. The class size is small. The population is structured and very well behaved, basically a 3 times you are out theory with behavior. You had to apply and be accepted according to your mastery scores, your grades, an application with an essay and past behavior. This does make it somewhat exclusive, which it can be, being a magnet school. The level of instruction is high. What is expected, is a lot.
My daughter has 2-3 hours of homework a night, 6th grade, and grades are dropped if they are late, no excuses. The school is brand new, going on it's 3rd year, thus no asbestos or other enviro concerns. It has an indoor pool, a great gym, Music center and state of the art technology, among other things. There is a Montesori Elementary, the Magnet Middle and the Academies of Art/Music and Science/Math for High School. It works with a local college, thus my daughter attends an excellent College for a few hours a few days a week.
Big minus for her Long Day and She Misses Her Local Friends.