according to my experience, both are same, both of them (ICO & IEO) have the same risk of high failure and high profits. My advice is to be more careful before investing in ICO or IEO, but if compared to IEO, I prefer ICO 
it is true that all fundraising will have its own failures, but when I have used the IEO and have started to enter the battlefield, I think the failure factor is very small because usually the place of exchange has selected projects that will be launched through the exchange.