Bitcoin vs Ethereum. Yes its true. Ethereum has all possibilities to compete with Bitcoin and if you can see it has almost 20+% of the marketcap share while bitcoin reduced to 50% from 80% over the past 2 years. Ethereum occupied market cap share what bitcoin earlier had . Also there are many tokens generating on the ethereum platform.These all shows the possibilities of ethereum as the toughest competent to bitcoin for sharing the marketcap.
So.Bitcoin vs Ethereum is my answer. But in few years I expect Bitcoin vs Ethereum vs Electroneum