You are doing comparison between 2 formost coins.
Btc and Eth both are leading coins in cryptos. These both coins have their own hold in the market. I would say dont invest all money in single coin. Invest your money partially in Btc and rest in eth. Both coins are suitable for long term holdings. To ensure stable and risk free returns invest in both coins.
That's wise decision, it is a free advice for everyone and for the safety of our own. For quick returns, we can find it through investing BTC as of now as ETH isn't moving high and there is more downfall than of uprising trend.
You can add more coins in your portfolio if you think that you can still manage them well but if not, you better stick into 2-3 coins.