EF is a franchise, so it's understandable that there are some differences in the management, policy, and overall working culture in some branches.
I believe some branches have good working environment. My office was not one of them, tho.
These are my assessment of the office I worked in, not the whole EF.
1) Unfairness. Local teachers have siginificantly less benefits compared to international teachers, even though they have more responsibilities and working period.
2) Messy management. There is weak unity and collaboration. Teachers are merely expendable pawns.
3) Questionable policies/rules. Many of them don't make sense. It gets even worse during Covid-19, especially for low tier and part-time teachers.
4) Little appreciation. They blame you easily for your mistakes, but almost pays no attention to how well you are doing your job.
5) Close-minded higher-ups. It's hard to share your true feelings, desires, or opinions. When they have "a conversation" with you, their first instinct is to be defensive or to shut you down, not to listen.
If you still want to take part in this company, at least pick a branch that has healthier working environment.
The company itself is not bad as a whole, in fact with better people, it could be the top recommended place to work. It has good curriculum and bank of materials and teaching activities.
If you could overlook some major flaws in the office you're working in, then go for it. At least you could improve your public speaking skill a bit if you're applying for a teacher.
You know well what you really want.
Teaching materials, the students, opportunity to polish your English and teachings skills.
Low benefits, low transparency, bad management, stressful and biased environment, questionable policies, little appreciation, close-mindedness.