Insead is over-rated, they are the most well-known only becuase a lot of senior executives study there. If you are interested in climbing the corporate ladder as a salaryman, then it would be the best place to get your MBA.

Chicago Business School is the one that you will really see the high society of Business / Investment world - very small campus in Orchard, but essentially it's a gathering place for the elite. It's a little like a club house for successful entrepruners, generation rich and top finance players.

As for the rest like NUS/NTU, I wouldn't bother no matter how cheap their courses are.