Participated at pre ICO is more benefit than you invest your money at ICO, when you make investment at pre ICO you got much coin with lower price than you are joining for investing at ICO time.
I consider the specific coin in the clay market first does the coin fulfill my needs and be worth investing? well that's what I'm thinking
if you are discussing a matter of consideration, maybe, what you need to prepare is your mentality, because we don't know when a project will scam. however, a team that is professional, and good in its field will not do that. besides, the concepts they make, and also the competition that exists is a pretty good consideration to do.