That's broad because there's lots school choice systems and they all approach it differently. There are systems with charter schools and there are systems that simply eliminate the neighborhood school requirements.
I think the charter system is flawed. First, if there are not enough charter seats for every student that wants to change school then there will be a funding problem. Most school districts move funding with the student. So if a student moves to a charter, his funding leaves his original school and goes to the charter. However, since the overhead of the original school does not change, this simply defunds the original school at the expense of the students who remain.
School has $500k @$1k per student. Teachers, electricity, buses, etc. all cost $X. If 10 students leave for a charter, the school gets $10k less. But they still have the same number of teachers, the same number of buses to run, electricity for the building remains the same. The school now risks a budget shortfall and the remaining will suffer because of it.
If the funding doesn't follow the kids then both groups benefit. The remaining students get better student/teacher ratios and the leaving students can go where they want.
If it's simply eliminating neighborhood schools, that can work fine since the total number of students and the total number of seats remains the same. The funding would remain consistent across schools.
But the 2 elephants in the room with any school choice program are simply "Do you continue to fund the prior school at the same level?" and "Do you have enough flexibility for every student that wants to choose or does it turn into a system where only some kids get the benefit?"
