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 
Both of risky that's absolutely truth but firstly you have to think crypto means your investment is involved with risk. ICO is huge risky comparatively with IEO. ICO project randomly failed but IEO means project listing confirmed before token sale that's why investors first recommendation is IEO.