I think Ethereum, but locking the investment in one coin for a whole year is a limitation by itself.
But you will gain for sure, so it's still a good call.
I believe we might see something that will replace Ethereum within a year. I am betting on ICON or WANCOIN. But no one knows.
I think ETH still be the best altcoin for this year.. we can see that a lot of other altcoins grow fast, but I don't think any of them can overtake ETH this year
I definately see ETH ending the year at around 5K but no one can tell. It is worth holding some ETHER