The main ICOs platform I use is the ICO drops and ICO hotlist, but as I know there are still many ICOs platform, while if any team has created an ICO project and ready to launch for presale / crowdsale, they will usually put a submission to the site. I am not sure how the platform would determine whether the ICOs are scam or not before they post it. So you may actually see not every platform would have the same ICO project, or a ICO project would not be displaying in every platform. That is the reason for me to use icodrops and icohotlist as I think their information are clear and trustworthy. It definitely takes time for you to experience more from different sites, while you may also think other platforms suits you too.
How I review an ICO, I do not only depend on the ranking or rate given by the ICO platform, I have some criteria
1. White paper , by viewing the content, how this ICO projects is trying to contribute, by any feasible method, any analysis, any reasonable prediction and actions
2. The team: not only the team and advisory profile, but also check how they contribute in their social media network, like the telegram group(no. of followers, how they interact, what are they posting), facebook, medium, twitter activities, how do they really know about the market, how do they contribute and trying to give to the potential investors.
I think this effort does affect my judgement to support the ICO or not, even if the project may not be successful might not directly means that the ICO is a scam, but definitely you have to put your own effort and time to investigate more and do not fully rely on any analyst comments.