Everything is new and and all these projects will run into unknown unknowns. They will overcome them and prosper or be overrun by alternatives that managed to overrun them. I have no doubt at all that a number of blockchains will survive the coming challenges.
I think Bitcoin is in a good place to survive thanks to the network effect and its size, but I think DASH is well poised to be the dominant competitor thanks to its innovations in governance and compensation.
Ethereum has interesting properties, but may be threatened now that RootStock runs as a side chain to Bitcoin.
LiteCoin does nothing interesting at all and I expect (or at least hope) it will drop.
PeerCoin does Proof-of-Stake, which may be interesting and from an environmental perspective the world would probably be better off if PeerCoin killed BitCoin, but it’s not likely.
DogeCoin may have something going for it if deflationary properties are not what people want.
MaidSafeCoin has some really cool things going, that will be interesting to watch unfold.
Ripple as a coin is not very interesting and doesn’t really compete in the same arena. The project on top of it is very interesting, but does it have any momentum? It seems have pivoted from marketing itself as P2P to focusing on financial institutions.