I really think these IEO thing is only good for the top exchanges and these is because they have the liquidity and the traders to pump a coin after listing, which is why their IEO projects are usually successful.
But the smaller exchange don't have the same and their IEO success rate is no way near the top exchanges. Maybe 2 out of 10 IEOs conducted on the small exchanges would succeed, while top exchanges boast of a success rate of like 9 out of 10.
The advantage of large exchangers is the large volume of daily transactions they have. This is different from small exchangers whose transaction volume is different from large exchangers and maybe this is what makes IEO from large exchangers always sold out in just minutes and makes the price of tokens go up high after the initial listing