IEO trend lasts for months and many projects I know changed their ICO plan to IEO. And obviously, IEO performed quite well. Like Huobi, Binance. While I am not so optimistic that it will live longer then ICO, Gate.io IEO is a disaster. And people start to lose faith in that. There will be nothing that will be living permanently. Same like ICO, the most important is do your own research, find out good projects and invest, that is the most important. Here is my list of projects that have the best future as of today (Including Alts):

Bitcoin
Ethereum
Stellar
Historia.network
BLOC
DGB