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.
Judging by this rating (
https://neironix.io/ico-rating), that ICO, that IEO are successful and not, but because IEO supposedly select exchanges for them more trust from the community, but you need to remember that they can bribe the exchange, so you need to choose reliable exchanges and still evaluate projects that go to IEO, it seems to me that IEO is a little safer.