I personally like the ICOs with existing running business. Because in this case, you can check their profit and loss and business model to judge yourself if there is a future or not. The problem is this kind of ICO is usually less "attractive" because they promise less than those who has nothing in hand.
Indeed it has it's prons, if you look at it this way. I will add it, but also keep a notice, that this may not go all the way.