Let's explore the question first. Let's wait for the first results. What would definitely understand that of the 2 types of project is better. I think if the project is not well-off, then nothing will save it.
Only time will tell if IEOs are really more secure or are subject to the same problems are ordinary ICOs. The due diligence exchanges perform may not be enough, just like pool due diliegence. An investor must always do their own due diigence.
The due diligence by exchanges can never be perfect as they are not God to know the heart of every investor and their game plans completely. IEO in the interim, can only assure the investors of a safe environment i.e. not falling into the hand of a scammer that is not known, so if an IEO developers scam an investors, at least, they will get the chance to be prosecuted if found guilty.
The issue now us that of failing projects which I still do not see IEO completely scraping this out, no matter the due diligence they perform in these projects, some of the will still fail in the long run, so I agree with you that we should not completely rely on the exchanges alone is making our choice.