They seem biased to me. A friend of mine who's doing an ICO told me that they paid 10ETH for 5 quality ratings and that's that! I noticed that some ICOs with good project, team, and good social media presence are struggling with getting good reviews.
With all that said, should it still be a factor to look at when investing in ICO?
I do believe on ICO rating sites. Although it is just a rating site, it shows the idea of the majority and it simply means that coins at the top are the ones which are having high demand. Therefore, there is a huge chance for the coin that is having high rating, to be successful due to the demand that it is having from the majority.