BTC and ETH are both too low, and thats because of the international fight against them, they call it regulation.
ETH lost more than BTC since DEz. 2017, and thats because there are no more ICOs on ETH, so no more need for that amount of coin.
to choose a Bitcoin investment, or Ethereum, try to see the difference in development since the beginning of 2019.
Bitcoin
January 01, 2019 the price of bitcoin = $ 3,746
Oct 05, 2019 bitcoin price = $ 8,135
Ethereum
January 01, 2019 the price of Ethereum = $ 133
Oct 05, 2019 the price of Ethereum = $ 175
with this difference, today I think everyone will prioritize bitcoin over Ethereum today. You can check the source price directly on coinmarketcap
This clearly shows who has dominated the market and provided more return on investment for the users but this does not rule out the fact that ETH is the only alternative if people want to experiment with their investment as the value of ETH was hardly $80 odd somewhere in the month of December 2018 but again it has bounced back. Market is going back to what it was earlier wherein the investors have lost interest in ICO's and new altcoins and shifting their investment towards BTC and ETH. I would invest in BTC as well as ETH anytime as these coins have the ability to go through numerous hurdles let it be market market situation or regulator's axe.