If I prefer IEO because is connected to the famous crypto exchange platform that needs to protect its reputation. They will filtered and checked before being published, which makes it significantly more difficult to deceive users, giving credibility to the project and security for users.
Why people trust Binance over other exchanges in IEO is because of their good reputation, and there's a hype in this site so they can expect an early return. ICO is already dead, I mean literally dead (sorry to say) as most of the new created coins now are already coming from IEO.