They both have probability to grow more this year. Actually it depends on you, but if I were you i would chose ETH than waves. 

ETH is more less like bitcoin, it has the vision of not only having a decentralised crypto currrency but also allowing decentralised applications to be created on the ethereum blockchain that use smart contract. The price also better than waves, and it doesn't drop that much in this January. It proves that eth fundamentally stronger than waves.

But if money is not your problem, it will be even better if you invest your money in both of them. It just a matter of time who will go up first.