When they are in the top 100, you probably already late! The risk is always there, so it's best to buy before, in my opinion)
Yeah, Whatever decision that you'll choose in here, first before investing in some project be sure to do your own research about it, and do it thoroughly, spend at least 20-30 minute each and check everything twice. There is more risk in low valued projects but ofcourse if they suceed gains are bigger. So do research not to get scammed or lose your money. Good luck mate.