I personally have experience with all three of the types of schools or students that you have presented, and I think you are misleading a lot of people. Here is why.

1) International Schools: These places are glorified training centers masqerading as schools. The one I worked briefly at was a BC Canadian certified place in Tianjin wrought with disorganization and mismanagement. The principal was a former music teacher from Canada with no management skills whatsoever and was extremely close minded to boot and a little bit of a bully. What's more they charge students 10,000 US Dollars per year to attend what is really a very mediocre place of education that would be at the bottom rung of any public rankings if they were a public school in any provinces or states in Canada and the USA. Bad management can lead to an actually worse experience than working at a small training center.

2) Partnership Schools: Again, this is a place where people looking to make a quick buck will come. When I was working at a public university in shandong, that university had a partnership with a private company and allowed that company to use its university name. The job of that company was to teach cram classes in computers. I knew a personal friend who worked at that company and she was screwed over by the boss. The boss of this partnership company basically mismanaged the budget and had to move out of the rented place which was right across the street from the university campus. However the convenient thing was the money that the students paid were not refunded. My friend was big hearted enough to give the students extra classes in her own home. There was another older teacher who also worked there briefly and quit before the place went under.

3) IELTS: This exam is used as a cash cow by many private places now. Each place will say that their method is better than anybody else's. However like I said in an earlier post (which you have failed to address apparently) socializing and looks go a long way. Personally because of my ethnic background I am sensitive to people stereotyping and pigeonholing me in a role, and that is one reason I avoid china, both chinese and expats there are just too racist. I taught at an IELTS place and I was put under closer scrutiny for the smallest issues be they real or imagined by students and upper management. They didn't like the fact that I was making equal money to the white faced teachers even though I was teaching 3 types of classes (regular, toefl, ielts) and the other white faced foreign teachers on equal salary were only teaching one (regular). I would certainly make less if I did private tutoring as they wouldn't pay as much money per hour. I and many others choose to stay away from the money part of the ESL industry because this is an industry that isn't worth losing our time and dignity over. It's enough we're in a foreign country and we need to become adjusted to that. I don't see china as a place to make good money teaching because dealing with the people brings too much stress and complications.

This is just my experience though. Of course you just take things for granted and believe everyone can make 40,000 dollars a year. You are in the minority of the esl expats and just by making this statement you will potentially ruin the experiences and hopes of many teachers. Anyone looking at your thread and just skimming it will try to look at the highest salaries that are offered in guandong and naturally they will not go to any public universities, but whether or not that is your ulterior agenda is something that remains to be seen and is certainly a possibility.