what cryptoocurrency do you think it will replace bitcoin if and I say bitcoin goes down for one reason ?
im afraid this will happen after all this things about bitcoinXT , censorship on reddit about it , people can't agree on one thing and this could be the reason of it's death and that's my opinion only and most of people may lose their coins if they don't know what they are doing
i don't think that Ethereum have a chance either, on the last hour according to marketcap it was like 65 million USD now it became 75$ million USB , alot of pumping going on and im more then sure it's nothing but regular manipulation that rich people do all the time with different coins .
If bitcoin project will failed , all crypto currency coins will failed .......... but if it could achieve successfully the alternatives are dash and monero