This is a very serious question mostly because the amount of money that people are investing in cryptocurrencies. We all know how volatile is cryptocurrencies market and that is the reason why many factors are included into the decision in what cryptocurrency to invest. If you are looking for cryptocurrency to invest in, here are some fundamental points that you need to observe before decision.
Rule number one, the older, the better. For example Bitcoin, Ethereum, Litecoin are good options from this perspective. Rule number two, always seek for the cryptocurrency that are investment for a long term. Always check what are problems and main ideas with the cryptocurrency and would that problem be solved in the recent future. For example Bitcoin is created as a alternative for a fiat money. Litecoin is created to solve some Bitcoin\'s problems. Ethereum is platform where people can be funded for their ideas and projects. Reputation and adoption rate are also key factors. Always do the research by yourself from the relative sites, never believe anyone about anything until you find out by yourself.
The main question in the decision in which digital currency to invest in may be the rate of usage, for example Ripple is used for the transaction between banks, including JPMorgan, which is a pretty huge bank. Technical aspect should also be taken into account. And of course price, always check the price moving in last week, month, years.