once u start asking how high the interest rate in case of late payment, clearly you are not advised to own credit cards. 

Google is your best friend to get more info.
Generally, Visa/MC charge lower fee for merchant when using their service.
Amex charge higher fee, hence less merchant signing up for their service.
However, Amex is lowering their fee nowadays, and it has getting more popular, especially in US.

In short, as a consumer, less places are accepting Amex.
Amex gives better return compare to Visa/MC.
For those places accepting Amex, go for it.
Those not accepting, use your Visa/MC (that's why Maybank give you 2 cards).
Premium business always accept Amex (ie. branded outlets, >4-star hotel).

Additional info, there are Amex Charge Card and Credit Card.
Maybank 2 card belongs to Credit Card.
You can search for their charge card and compare the privileges.

Last but not least, always settle all your monthly billing and won't bother of late payment fee.