Can somebody explain to me what the main differences between NEM and Etheruem are?
You're in the wrong place. This is the ETHf pump and dump thread.
Is that dumped to the ATH again?
Suckers that missed bitcoin and now can't afford to buy one whole bitcoin are buying ETHf hoping that one day this pump and dump coin can do what bitcoin did. They just forget that in contrast to bitcoin ETHf is a coin of unlimited supply. That is the main reason that among all altcoins ETHf is bank's favorite coin. XRP is the second one for the same reason.
But there are fundamental reasons why it rised so much to be the top cryptocurrencies just after BTC getting there before competitors. It's flexibility, programmability, token creation, gateways to other alts with liquidity, fast adaptation with bussiness. These are aspects which BTC doesn't have. And all what BTC lacks increases valuation of coins which acually are doing.
Question is if this wave of investment moving downside from BTC to ETH than to Ripple, now maybe Dash and further will last. If you have a big wave comming into alts it's obvious it will be first a pump affecting top coins proportionally but next there will be free market redistribution to find real valuation. After phase when all might rise there will be next when you will see good projects rise much faster.
I don't think ETH will loose momentum because of tech that is backing it, and Ripple does, since it will go up only to get equilibrium in overall price by it's place in top, nothing more (still nw funds certainly boosts development but only as late effect). Maybe next coins will take over place of Ripple too.