I have worked with this company (Guangzhou Worlda Educational & Cultural Consulting Services) for about five months now, and my experiences are much different than those described above. No one kept my visa, they got me a residence permit so I can live and work legally in China, the staff is friendly, and Mary Yuq is not the devil.

This is a teaching agency, meaning they send teachers to primary and middle schools, and they pay you your salary (the schools pay them). This is not a dream job by any means. However, it is a good stepping stone into teaching in China. Also, the money you get is enough to live on, unless you want to live lavishly or only eat/hang at Western establishments. In that case, it may not be enough money. I personally have always had extra money in my Chinese bank account.

Most things in China can be established by negotiation. Remember to remain polite but firm. This company is fine, but I would not recommend going through other recruiters, because they will take more money from your salary. If you want a high-paying job, this may not be it... although you will probably make more here than teaching at a university. However, a university position would be more relaxing. Read general reviews on teaching English in China to know what to expect, and how to deal with it.