I live and work in China. I just did a TEFL course. I researched CELTA but its so expensive to take 4 weeks full time off work! I did my courses with Teach-the-world and I-to-I. Yes I did two of them!
I preferred some bits from I-to-i and some stuff from TTW. You can basically get any CERT to teach in China. The main things you need is a University degree.
I recommend either of those companies above. I did I-to-I over a year ago though, that's how I got in to China, then I did Teach the world recently.
If your still serious about teaching after a year then do the CELTA. At least that's my opinion, I think its good to do the distance learning first, go to China and get some hands on work and build your confidence up and get some practice lesson planning.
Then do the CELTA after a year or so. Its really intense from what I hear and not necessary as it promotes all these methods and techniques that aren't always appropriate or practical to use different cultures. I have some friends who rave about the CELTA but they all agree its virtually impossible to use what they teach you in China due to cultural difference and expectations of learning. Something to do with memorizing VS student centered learning. That will make sense once you have taught for a while!!
Remember the way in which people learn or belief teachers should act is different in each country. Its all rubbish really about the teaching methods. Just get a simple cheap Cert and get into China:
Teach the word
Hope that helps ^_^