Hey Yingwen, Although I haven't acknowledged it before, we do know each other. In fact, after one of my postings under a different pseudonym last year, you questioned whether or not it was I, but I didn't respond - wanting to stay anonymous and all that. However, since I see that you are looking for a new position I have one or two recommendations that I'll be happy to send you via email if you care to give me your address.
In regards to private schools and specifically the chain schools, I'm sure most would agree that they are best avoided for a variety of reasons - the least of which is that even if they are foreign owned, they are rarely foreign operated. Schools such as EF, Web and Aston, it can be seen by reviewing the archives here and researching elsewhere, talk the talk but rarely walk the walk. The managers or leaders that one talks to are usually Westerners that are adept at painting a glowing picture, but once past that point the image begins fading. (At one point last year I was hired by Aston as a manager for one of their newly opened schools. They were very effusive in their praise of my qualifications etc., but before I could begin I had to rush back to America due to a problem with my family. At that point their kindness was proved to be false - no further communication and no show of concern. In short, by taking no action on my behalf they showed their true colors. And we all know what color that is; "The Color of Money.")

Having said that though, I know from personal experience that there are a few training centers that are worth looking into. I did a two week gig this summer with a private school after the term ended at the university where I work. There were four other teachers there and none of us had any complaints. The manager is British and quite easy to get along with. Generally, their focus is on IELTS and most of the students are motivated young adults or adults. The training center itself is up to date with comfortable class rooms and a nice surrounding. At any rate, though they're looking into opening another school here in the same province, they are not a chain school.
If you'd like more information, I'll send it to you in email. Until then.........take care.