Both are very solid and have great potential for 2018. Expect to see them both gain more traction in Market Cap and price. Smart Contracts I believe are one of the best Crypto investments. In the past I have been drawn into various ICO and cryptos based on hype/advertising and then realised I was basically backing projects which had very little reason, and certainly no "urgency" for investors to back them or purchase the coins.
However with NEO and ETH and other smart contracts there is always an immediate need for investors to buy the coin if only to use them to get into new ICO's built on the NEO or ETH smart contract, plus those investors who realise they are in demand and are therefore a good medium/long term hold.