I think it depends on what you are looking for, it terms of potential growth and profit I will go for Zcash but what you get with Bitcoin is value, trust and solidity
Bitcoin fulfills potential growth and earnings conditions, apart from value, trust and soundness.
Bitcoin is a much more profitable investment tool when it is considered long term. And the end of the altcoins does not end well. Many people are losing money by investing in altcoins.
My preference is
BTC