Ethereum and EOS are both good coins, but ethereum has been very popular since 2015, as it performs significant maintenance work for the ICO, which is more than 90 percent carried out on its platform. EOS is a similar coin and in the future can fully compete with such a strong coin as ethereum, because it has a higher technology. However, EOS is still a very young coin and needs more time to prove its necessity and usefulness. I think that ethereum is still needed in the first place, but it is also necessary to purchase EOS, while it is still very cheap in price.