I would prefer ICO because most of the time IEO are instantly filled up. ICO back then is powered by the community while IEO its the whales that are buying the token.
Who told you that whales did not buy in ICOs? Whales will always buy in any project that can make them money. The same way they buy in IEOs is the same way they buy in ICOs. In fact they made buying ICOs very difficult for investors who have few cash to throw around as they took up buying space and make traffic heavy on those sites. Anybody buying ICO is exposing himself to a bigger risk than those on IEO.