Pros
From my experience the whole beginning process from application to the first day of work was professional and painless. (Having said that I know it's not been the case for everyone especially where visas are concerned) The pay is okay, the students are great and also willing to help you. If you want to take the initiative there's opportunity for professional development. EF is a Trinity Dip TESOL course provider and they also run various distance learning courses throughout the year. The teaching material works on a cycle so it's easy to get used to and the adapt as the cycle repeats. There's scope to be a little creative with that, and also other types of classes that have no fixed lesson plan for you to follow. Working with Chinese teachers is a definite advantage and management in my city seem to listen to staff.
Cons
From my perspective the hours suck and everyday I go home drained. That days are too long as you're expected to be in the office for 9 hours (including lunch) especially taking into consideration that it's also a late working day finishing at 9:30pm on weekdays. There can be some flexibility depending on your centre but smaller centres get hit hard as there aren't enough teachers. Being on the opposite schedule to everyone else in the world means you'll probably only end up socialising with other teachers if you hadn't made friends in China before and learning anything but survival Chinese is but a pipe dream for those who hadn't studied before. You're likely to come up against the usual gripes for working for a large company and maybe some additional ones because of cultural differences but these are largely manageable.