Difference between "Chi bao le ma" and "Ni hao ma"

My dear friends~ Chi bao le ma?

A facebook friend of mine asked an interesting question~
"What's the difference between [Ni hao ma] and [Chi bao le ma]?"

As greetings, both『 Chi bao le ma 』and 『 Ni hao ma 』are similar to "How are you? (in English)"
Both 『 Chi bao le ma 』 and 『 Ni hao ma 』 are very common greetings in Chinese.
In fact, there is no big difference.

If you must distinguish them, you can do like this:
『 Chi bao le ma 』---> used in more casual occasions
『 Ni hao ma 』---> used in both formal and casual occasions

Therefore, You can use『 Chi bao le ma 』between friends.
In formal occasions, 『 Ni hao ma 』is used.

For more information:
Ni hao: http://mandarineveryday.blogspot.com/2012/04/greeting-ni-hao.html#links
Chi bao le ma: http://mandarineveryday.blogspot.com/2012/04/greeting-chi-bao-le-ma.html#links