i think in this 2018, it will be the most profitable if we choose to invest in Litecoin or Monero, due to demand for Litecoin is increasing making it harder to buy, so the price is increasing everyyear, its transaction is much faster and less fee than Bitcoin, so there have been so many investors use LTC more and more, Monero has super anonymous wallet so privacy is more appreciated by many investors want to avoid governments all round the world, so in the future, when governments want to control cryptocurrencies more than investors will use Monero more and more making value of Monero will rise in the future.