I don't believe in ICO ranking sites. Most of them are paid and not real. The more they get from the team (payment) the better the rank they will give!
What I am looking for in ICO is looking at MVP, live and working products. Something that really can make a difference. Not just empty words with fancy pictures.
I know it is very difficult to know when an ICO is a scam or not, but I tell you that there is always a way to find out. First of all, if the team behind the project don't have anything to hide, then they should do weekly Webinar with their investors telling them about how the project works and also answering questions that would be passed on to them, but many ICO in existence this days don't do this because they don't have good intentions in mind and will never want to release their identity for everyone to see.