I am just going with Ethereum, I guess, because we know Ethereum is the most stable altcoin among others. And the profit it gave was greater than any other coin. Because in the future, Ethereum will have more scope than Bitcoin. I know some traders and my friends who are holding more Ethereum than Bitcoin. The major reason for considering Ethereum is because of the advanced version of block chain technology compared to the Bitcoin block chain. The transaction time is shorter, more user-friendly, and there are more transactions at the same time as compared to the Bitcoin block chain. Maybe in the future, invent a better technology than now to resolve the current default.