I don't usually review places, but I saw the review from 22Yossarian and felt that it didn't fairly reflect i2 in my experience. I only have 3 days left before I leave the company so I don't have any real motive to write this. - I'll say now, it isn't a perfect company, but speak to someone who is currently working there if you have any doubts.
I am one of those 'veteran' teachers mentioned by 22yossarian who has been teaching English for over 8 years, two of which I have spent at i2. Currently at the campus I work at there are 2 other teachers with over 5 years of teaching experience, who are happy working here.
For me, I have found working here challenging, rewarding and enjoyable. I think it is important to acknowledge from the start that as a training school, there is always going to be an aspect of business to the job. The contract I signed was very clear about my responsibilities and duties and at no point did I ever get asked to do anything not covered by the contract. - be sure to read it before you sign if you have any doubts, however I found it pretty common sense.
Teachers have access to some materials, but I'm actually quite grateful that they allowed me some flexibility on how to deliver the lessons to allow for individual teaching differences. As such I could choose to use my computer, or my own materials to teach - although the curriculum is set and follows a set of Macmillan published books. The books aren't to everyone's liking, but I think they are very good - as do most of the experienced teachers.
I've certainly not had a flawless experience, but the parts that challenged me have generally not been in regards to the company or the staff, but rather the nature of training schools. For example, at first I didn't enjoy teaching demo classes for new students during me prep time.
Also, I actually worked at the campus with the sewage pipe burst. - it was pretty horrible and ruined the teachers' room and stunk the place out. During this time, the teachers' room was closed and we were asked to prepare in our classrooms in another building so there was never any need to go in there. Though the leak was plugged to prevent any flooding or damage, it wasn't repaired for weeks since the landlord who owned the restaurant above our office refused to turn the water supply off so that it could be repaired.
I'm leaving China next month, but if I weren't, I would likely be staying at i2 for another year. I don't think I'm immoral as a result of saying that, nor do I think my colleagues are. I have seen my students grow a lot in my time hear, and by far the best part of my time at i2 has been teaching and working with them.
In short, I liked it and have no regrets. If you have doubts, ask to speak to some current teachers. Usually the ones that have broken their contracts or been fired seem to have a negative perception.