What do you mean by that? all of the ICO's are selling tokens during their crowdsale and private dealings but some of them turn out to be fraud ones if you are talking about released coins on the exchange then that is not the pure basis for determining best ICO, well for the OP ratings will not fully help you in finding those hidden gems and legit ICO's even some scorers online can be paid to have a good ratings or to gain some premium listings so don't fully trust the ratings, they help but not to the extent that it will be the best option.