I completely agree with mac, sgvaibhav and nitcomp
IGCSE is a much more sophisticated form of education. The standard of English in CBSE cannot even be compared with that of IGCSE. For CIE IGCSE Literature we have to write four essays with open books while CBSE students 'fill in the blanks' and give one-word answers, trying their best to recall all the information in their books.
IGCSE focuses not only on knowledge but also on the applications of knowledge to things in real life.
For example, you can take French, a subject CBSE gives little importance to. IGCSE covers all aspects of French including Speaking and Listening. This is actually has practical use rather that mugging up tons of words and phrases.