Go to Dave's EFL Cafe (Google it) for info on particular schools.
China is the third largest country in the world, and it has a population of 1.3 billion people. Asking where the best place to go is both meaningless and impossible to answer. The weather, the culture, the landscape is so varied, that what is the perfect place for one person could be someone else's worst nightmare.
I like the South West personally. I like the weather, and I like being close to Hong Kong. I like the Cantonese people, and I love Cantonese food. I like being near the sea. I like being close to other South East Asian countries for when I have holiday time. I don't like big cosmopolitan cities, so I wouldn't teach in Guangzhou or Shenzhen. Too dirty and too many other foreigners for me. I didn't come to China to hang out in Western pubs and restaurants with other westerners. Other people love that lifestyle.
Salaries are better in big cities, but so are living costs. You may have more spending power in the more rural areas than you would in Beijing of Shanghai for instance. The rates are worked out so that it evens out nationally. You should be earning at least two to three times the local cost of living. There are good and bad schools everywhere in China, it's best to do your research before accepting a job.
Dave's EFL Cafe is one of the best sites for researching good and bad employers as well as getting info on a particular city or town. Don't go to China until you've visited www.middlekingdomlife.com
and read as much as possible.
Before you fly out, leave any and all opinions and expectations you have behind, and under no circumstances try to compare anything in China with what your familiar with back home, that way you will have the time of your life.
Be the change you want to see in the world.