The best cryptocurrency to purchase is the one that you want to hold on, whether the value goes down and goes up. I believe Bitcoin is the type of crypto that I am willing to hold even it totally goes down and will buy more eventually when the price goes really down. I don't have any intention to sell these tokens and continue to invest in the long term because I believed that there are community behind it. One more thing focus on the established one. And only invest to what you can afford to lose.