Eth follows the flow of bitcoin price, and eth is the second coin after bitcoin even though there are some coins that are higher than eth price, but eth is still the best choice of other altcoins.
It follows bitcoin closely because of its market volume of trade. This volume is going to increase more as the days go on as awareness for its use increases. Ethereum is priced below its worth in value because it is supposed to be close in price with bitcoin if not even higher than bitcoin. It is a means of payment like bitcoin and then has a contract others make use of.