COSS is interesting, but I have to say the exchange looks very amateury at this point. As for Centra, this article doesn't paint a very pretty picture of the people behind it: https://www.nytimes.com/2017/10/27/technology/how-floyd-mayweather-helped-two-young-guys-from-miami-get-rich.html
RE: The Best 3 Coin Investments for 2018!