I would rather recommend IEO for an investment over ICOs, try looking for ICOs that have real addresses and you know one of the developers who has a good track record. I don't really recommend to fully trust the ICOs rating site, it would be better just to take information from them. ICOs that have transparent information has the possibility to be trusted, and vice versa.
there is no big diffrent between IEO and ICO , they are selling coin and have big potential to became scam or failed project if no one investing on their project, but yes IEO is more recommended than ICO that we are not really sure when they are gonna list their coin on Exchange or they are planned exited scam before its listed on market, both IEO and ICO investment are really have big risk of failed project and end up scam or abandoned.