Really i don't think is ok to invest again on ICO, this is just my opinion and anyone do what they want with their money, but some IEOs can bring a profit in my opinion even if this can take more time.
The IEO is just a form of calling capital through exchange. It only takes a fee (equivalent to the exchange list fee) to be called by the security floor. This only ensures that after the call, the project will get an exchange list (which means that the ICO is 0% white) but does not mean it will be pumped when the list.