Dash is pretty old altcoin but bitcoin will always dominate market, Ethereum has lots of potential and price & demand for ETH is already rising.
Bitcoin will always be used as payment method while ethereum will be used to invest in ICO and to gamble in smart contract based platform like vdice, cryptokittens etc.
ETH can have many applications while bitcoin will be kind of crypto payment.
Agree but the danger for ETH is that their blockchain can be stuck with transactions caused by for example these kittens.