Bitcoin or Ethereum, Which of these coins will rule in 2018?
As has long been known and probably will be so. Bitcoin will be something like a symbol and it will go up it's understandable, but use it as a payment system for the transfer of value, few will be, all because of high commissions and long processing operations. But ETH das a lot of percent in 2018 than bitcoin (very cool technology) - it's short. so bitcoin is a calculator in the ETH global super computer.
Some people are selecting ETH over BTC, this is not a bad take, but it's better to value both of them. Because BTC started this concept, and ETH changed the future of this weak concept with smart contracts.