ETH is going up fast 45% alone today, now it has the market cap 70% of bitcoin.
It has no doubt ETH will become the biggest and new normal standard as CryptoCurrency and displace bitcoin aka "Chinacoin" before the end of July.
There has been a lot of debate about the "flippening" as most people call it. The current issues with Bitcoin are related to its scaling problems. ETH fares no better on that front.
Honestly, I firmly believe that there will be several strong crypto-currencies in the future. Just like there are several strong fiat currencies. It's extremely rare that there's only one of a kind in any given situation.
In fact, I can't even think of a case where there is only one of a kind. There's always variations or copies that perform well on their own of anything that I can think of.