As you know IEO trend is growing but i feel IEO is profitable only for those who invested in token sale but who have purchased altcoin after launched they suffer loss majority of the investors ,as the BTT and some other altcoin examples of IEO.
To say the truth IEO investments are more profitable than ICO investments thats why many projects dont last an hour when IEO sales is going on,IEO projects that are been launched on biggest exchanges most times last only in seconds before sold out,this proves that IEO is more effective at fundraising than ICO but mind you we still have good projects that uses ICO for fundraising as well so the best thing to do is research on any ICO OR IEO peojects to find out if they are good enough