I agree with comments on EF! They have a really bad reputation in China.
Like the others have said, you will have a difficult time recruiting white monkeys.

Linguaphone and WSI I have never heard of.

If you are looking at opening a kids schools, I would look Joy English.

I have worked there part time for a year and their material for kids is pretty good.
They have material from about 5 years to 15.

More importantly they have a management system that seems to work pretty well.

The school seems to run itself.

There are a few issues with the boss, but you never see the guy.

As far as places go in China, it has actually been a decent experience.

You will need about .5 to 1 million to open a business.

Also starting a kids school is hard work. Don't expect to make much if any money the first year. But as long as you do a good job your students (at least some of them) will stay loyal.

For example in one class I teach, most of the kids have been studying with the same school for over five years.

Just my two cents worth.