Both eth and btc the best to spread your investment. 1btc and 10 eth it has been valuable and profitable in the long term investment. Eth could vary the price to be huge when you hold it long term. Btc price can be double or more than the current price today. So both for me eth and btc.
I agree, I'd say we better split 50:50 for BTC and ETH.. both are a good investment for the future..
But if you ask me to choose, I think ETH would probably give more benefit in the future, as ETH showed a better performance in this early days of 2018