There are two kinds of ICO from my point of view, the first one which has something called as soft cap and a hard cap, and the second with none of these (soft cap and hard cap). It's always best to go with the first one because if you invested in their project and they didn't raise enough money to reach the soft cap, your money will be refunded. The second one, however, is mostly a scam ICO with only one intention: to take your money away as much as they could. They will usually hire a well-known bitcointalk user with a high rank like legendary or senior member and has a too-good-to-be-true promises/benefit if you invested in their project.