One of the things I know up till now is that most of the projects that carry out the IEO on an exchange, 90% of the tokens or coins from the project will be directly listed in the that exchange. Liquidity and security issues are also one of the factors considered by investors.
The bad side.
The possibility for manipulation still exists as long as transparency is not really implemented.
Correct, IEO is still more profitable and its easy to acquire capital rather than ICO, and majority of the IEO was listed on that exchange which is a good thing, when it comes to traders and investors.