It is actually very difficult to say which cryptocurrency is the best for an investment.
There are different strategies that you can use for a long term investment and the first one is to invest on the top 10 cryptocurrencies by Market Cap.
It is wise not to only invest in one cryptocurrency, but to diversify so your winnings can make up for your loses.
A second strategy is to invest in cryptocurrencies that are still under $1 per coin, in the hope that they will gain in value in the future.