As Tim said, it really does depend on what school you go to.
The only thing I'd caution with EF is that is very much a business; money comes before education, every time. I have worked for different EF Schools in China over the last 3 years and the educational needs of the students always lose out to profits. I can't take it any more so I'm heading back to Europe to teach in 6 weeks.
If you care about what and how your students are learning, I wouldn't recommend an EF school for you, I wouldn't recommend any private school in Asia, to be honest.
My personal experience with EF has been that they are happy to put students in to the wrong level class because the time is suitable for them, classes that are clearly struggling will be advanced to the next book, despite the clear need to repeat a lower level. All because the schools are worried about losing the sale more than they are about the educational need of the student.
I'm sure that there are some schools where this is not as much of a problem, but the 3 I've been to have all fitted that pattern. The hours are much longer compared to other private schools in China, too.
If you let us know which area you're thinking of going to, we might be able to give you more concrete information.