Pros
Building relationships with students was the best part. I was honored to be welcomed into many homes and learn about another culture. Before I went for 2 years, I did a month program at a middle school, and despite having an ineffective team leader, it was a great experience, making me want to come back.
Cons
Communication is terrible. There is a strange culture of secrecy that seems to be: If we keep you from knowing how hard it is to work at this school, all the issues with school leadership will just disappear! And then when it doesn't go well, your supervisor (who lives in another province) blames you because he wasn't told how bad the situation is and thinks it's all in your head. My 2 teams were both quite dysfunctional, one because a couple wasn't interested in being part of a team, and another because of absent team leadership who preferred to pretend that problems didn't exist and a team member who was more of a liability as a quite immature man. We were encouraged to view students as projects, numbers to tally to send to the donors saying what a good job we did, converting and discipling this many people. Some teachers inherit study groups when they come, and others experience a much more hostile environment. Because we worked quite far from the Beijing head office, it often felt like our team was abandoned. Teachers closer to Beijing enjoyed group weekend and holiday retreats while we weren't even invited. Some schools and cities provide far more resources for teachers while others have nothing but a hostile relationship. As a first year teacher, there was no work/life balance. There was no support provided after returning to the States and barely any while I was there. Because some teams had more advantages than others, it was easy to think that you had failed when it was really the situation, or the school leadership, or the team leader, rather than it being all your fault. I was depressed for years after returning, convinced that I had been a failure when the truth is the organization simply didn't provide us enough resources to succeed and then blamed us.