There are a few but major setbacks here.
1. The CEO is always negative and unappreciative of your work on your face. Even though he would praise your work in front of other people behind your back, but to your face he will always be negative.
2. You learn a lot and work on anything you want to, but there is zero guidance. No fixed plans, and a lot of micromanagement.
3. The company atmosphere is like a hospital. You are not allowed to talk or take breaks. 9 hours sitting is a must. But you will only be ever appreciated if you stay for 12 hours. It definitely gets on your nerves.
4. Don't ever expect any growth if you are not looking to slog 14 hours a day and most of your weekends.