Hey. Although of the three places you are considering I've only been to Beijing, I received my CELTA from International House's teacher training outfit in New York - Teaching House. Although a tough, intensive four-week program I would definitely recommend International House. Plus, my CELTA trainer worked for IH for a number of years in the Czech Republic and had nothing but positive things to say about it - like, for example, how they paid for her to obtain further certifications for YA (young adult) and eventually her DELTA.

Hope this helps. I also hear Costa Rica is a fantastic place. I guess I would say take the CELTA any place where you are comfortable. It is too much work to be worrying about anything else.

Patrick