I prefer to hold ethereum by 2018 because this is the most popular crypt o currency after bitcoin. Ethereum is processing a lot more transactions and this is a very important aspect for a cryptocurrency. The day to day trading volume of ethereum is also quite high and market prediction is 2K to 5K in 2018. Ethereum is easily exchanged through the market. The feasibility of ethereum transactions is within seconds and developed as a platform that facilitates peer to peer contracts and applications so it is one of the main currency crypt among alt coin.