As you know IEO trend is growing but i feel IEO is profitable only for those who invested in token sale but who have purchased altcoin after launched they suffer loss majority of the investors ,as the BTT and some other altcoin examples of IEO.
I mostly like IEO because for ICO we have to wait for long time that after finishing ICO token will come to market then profit or loss. But in IEO we can see present condition of market and if we include here roadmap plan of that company we can easily buy token in IEO or not.
So i think IEO is best.