As for now basis, IEO give much profit because the hype created by that exchange. With the name they can grab a lot of buyers even the buyer really not familiar with the project. Like what was happened on celer token which token sale occured on binance, i buy the token not because i like the project, i bought it because it was managed by top exchange. Thats the difference betwwen ICO and IEO
Well, with the support of reputable exchanges and as a new trend that can be profitable in a difficult period, the IEO is really better and growing than the ICO when ICO maintains a bad state, too many scams. However, we can see that the IEO trend will not last long when too many projects are starting to bring less profit, the competition is also higher, a lot of people are showing a discouragement when they cannot buy during the IEO period