BTC for sure. BTC is the titan of cryptocurrency and I don't see how it could be replaced. I am 99% sure that BTC will be worth more in 1 year then it is now. I am not sure if ETH will be worth more in 1 year from now.
I don't think so . The Ethereal market is much more developed than Bitcoin, Bitcoin takes seven years to get $ 3500, while Ethereum takes just two years to reach $ 400. I think in the future ETH will dominate this market and Bitcoin will be the baby of ETH