This is a multi-faceted issue that I simply wouldn't generalise about.

On one hand, TCs in China exist to make money, education is a business and as such education is more often than not the secondary priority (if one at all) to the owners and management team. This results in incredibly dubious and unethical treatment of students (by the system) and can make it very difficult for teachers to do their jobs.

I feel the lack of regulation of teaching standards in China is the biggest problem. If regulations were tighter and only properly qualified teachers could enter China in order to work, then it wouldn't matter if they were working for a TC, a public school or a university. Teachers who are there to teach (not to fund an extended holiday) care about teaching standards and as such the standard of teaching remains high. The fact that there is such a demand for English lessons in China would mean that schools had to pay better wages and offer more competitive packages in order to attract qualified teachers that are allowed in to the country to work, putting an end to under-qualified native speakers who just want to fund an easy lifestyle. Put the focus on the teacher and the standards would rise.

On the other hand, so long as you are a good teacher, it shouldn't matter where you work because you can deliver high quality lessons in most environments. A good teacher doesn't rely on interactive whiteboards, bells and whistles and props to make a good lesson. So long as you are dedicated in your work and take time to prepare a good lesson, as soon as the classroom door shuts the politics no longer matter, what the students learn is down to the teacher. If the textbooks you are using aren't worth the paper they're written on, supplement them. There are hundreds of websites that offer free teaching material, you just have to have the dedication to look for it and pull it together in to one class. Your duty as a teacher re to the students in your class, not the school you are employed by and so long as you keep your students as your main focus, you can do a good job..

My personal feeling is that at the end of the day, whether your students learn or not is very much down to the teacher. If you teach well, your students will learn. If you teach badly, your students won't.

Unfortunately good teachers are few and far between in China and the combination of greedy business practices and having to work with people who care more about their social lives than they do their students education means that most good teachers don't last long in China. Generalising TCs or companies does nothing but give false impressions and perpetuate horror myths that only serve to keep good teachers, who could make a change at a local level, away from China.

There are major problems with the education system as a whole in China, and there is no quick fix. So my take is that if you are in China teaching, do your best for your students, prepare good lessons and don't get too upset over things that you have no control over.