I am about to leave teaching in China, to return home and resume my previous career, and thought I would share some thoughts.

First of all I have taught at private universities and a private language school.

The benefits of a private university/college are the working hours, on site accommodation and holidays.
The disadvantage of these degree level colleges are large class sizes, students sitting in rows, little opportunity to get them talking, most of the time they listen and write down vocabulary. You may have to prepare a lot of material as those provided are limited and usually not very good. Usually 20 classes per week but with a lower salary and benefits. Some are unable to provide visas.

In the case of the private language schools such as EF, WEB international, Kings, the company is a business and the level of job satisfaction will be directly related to the quality of management.

In my experience a good education manager will treat the foreign teachers with respect and provide structured materials for each class. Working hours are anti social, evenings until 9pm and weekend working. 25 classes per week but you will be in the office for 40 or 50 hours.

Where the management is poor, driven by profit and with little care for the reputation of the school or the quality of teaching, the work is difficult and frustrating.
Planning, communication and co-operation with teachers can be very poor.

Part time teachers tend to vary in ability and the full time teachers have to sort out the problems once they leave.
Private school salaries are higher than colleges, however health insurance may not be great, i had a problem and found the insurance was useless. Salaries and benefits have not risen in the last couple of years although expenses in my city, Fuzhou, have increased 50% for such items as rent, dining out etc.

The students of the private language schools concentrate on IELTS students, those wishing to go abroad for study or work with foreigners.

I have found adults easier than children and prefer to teach 16 plus.

Teaching can be enjoyable however i think 1 year is enough. I have completed 2 contracts with a private school and 1 contract with a college.

Good luck.