IGCSEs, GCSEs & A Levels

What are the difference of the three and which of them would be the best to take up? From what I understand, GCSEs and A Levels are equivalent and globally accepted… I’m not quite sure if the IGCSEs are as well. Someone please clarify. Thank you.

GCSE is a British compulsory HS curriculum in the UK. Students finish GCSE program at the age 16. GCSE certificate is roughly equivalent to US highschool diploma without AP classes.

A-level is a continuation of GCSE for 16-18 years old students (grade 11 to grade 13) to prepare to apply to UK colleges.
A-level is roughly equivalent to US AP classes or some first year college classes.

IGCSE is the international version of GCSE. Some people say it’s a little bit more harder than GCSE.

https://■■■■■■■■■■■■■■■■■/question/index?qid=20080506075627AAHo5h1

http://www.igcsecentre.com/what-is-igcse/

http://en.wikipedia.org/wiki/International_General_Certificate_of_Secondary_Education

http://ask.cie.org.uk/system/selfservice.controller?CONFIGURATION=1035&PARTITION_ID=1&TIMEZONE_OFFSET=&USERTYPE=&CMD=VIEW_ARTICLE&ARTICLE_ID=5448

IGCSE’s are a bit harder than GCSE’s but are basically the same level, a strong 10th grade curriculum (and you can include classes that would be similar to upper-level US HS classes).
A Levels are the next 2 years, equivalent to 11th and 12th grade with super APs (1 A-Level = 2 APs or one IB HL.)