Both are good variants for investment. Bitcoin remains the most popular option for the accumulation of assets. It gained good reputation and didnt lose the leading position in terms of price and reliability. Nevertheless, it doesnt mean that investors are not interested in ETH. Considering the youthful stage, the growth of ETHs popularity is impressive. It ranks 2nd on the market capitalization and trading volumes after bitcoin. ETH developers took into account weak points of bitcoin and improved the technology with much quicker transactions and lower transaction fees. But at the moment ETH cant keep up with bitcoin's price.