Great question, I myself have met many sites with similar ratings. And I do not understand what their assessments are based on. By and large this is all taken from the information that the developers themselves publish .. but still, can not you buy this rating on the sites, and some scum can have a high rating.
And we know cases when high ranked ICO turn to scam. May be some ICO couldn't believe that so many investors bought their tokens... and just doesn't know what to do now 
But the same time I trust ICObench for example. And I want to believe that some experienced guys can separate cool ICO better than I.