A couple I've been watching:

* Stellar: scaling and extremely low fees, with basic smart contracts. uses federated Byzantine agreement instead of proof-of-work or proof-of-stake

* RaiBlocks: scaling and zero fees, no smart contracts

I'm really loving RaiBlocks too. My main concerns now is that there's no financial incentive to run a node, and the current price seems fictional (because 99.98% of the supply is locked up in wallets). I have high hopes for it, though, I read the whitepaper and nothing stood out as a huge problem, which is good.

The worst whitepaper I've read recently was for something called Verge, which was basically "we're gonna run a bitcoin wallet over Tor for anonymity you guys!"

800% gains in the last few weeks, Verge.

And they say it ain't a bubble...

My bet is on DPOS systems. They will not be as decentralized - but at at least they should be practical.

But it is also possible that Lightning (a second layer over the bitcoin base) will prove to be a good solution.

you should check https://raiblocks.net/

Cardano

Voted you up. I think if people looked into how Cardano does what they do, they'd realize it "cures" all of the ills of Bitcoin, Ethereum and every other unscalable PoW currency in an elegant, provably correct way. I personally think the future of cryptocurrency is going to look far more like Cardano than Bitcoin. Not saying any of the top contenders are going away, they just will be glued/superseded by something like Cardano for more or less anything these others aspired to become, e.g. microtransactions, better/nearly infinite scalability, etc.

PoW is not ecologically friendly, and that will be one of its growth inhibitors.

Ripple

https://ripple.com/xrp/market-performance/

Isn't it closed source and run by a single corporation? What's the benefit of being tied to a block chain if for a centralized currency? Just copy the current visa/banking system and you're good to go.

No, its open source: https://github.com/ripple/rippled

> What's the benefit of being tied to a block chain if for a centralized currency?

https://ripple.com/insights/the-internet-of-value-what-it-me...

Ripple is interesting. If you're a true believer of the decentralized concept of crypto, you shouldn't like Ripple because it is controlled by a company (but is open source, similar to Java), and many financial institutions use it. So it's kind of towing the line between centralized and decentralized.

Not sure why you're downvoted. Thanks.

IOTA is probably the best at both of those

Have you actually tried to use IOTA? It's really bad, you get different balances depending on which node you connect to, sending is weird, odd things like that.

Given that it currently depends on a centralized coordinator, that seems unlikely.

So far IOTA is centralized, it relies on snapshots. It is just my intuition - but it does not look like "the tangle" could ever be decentralized - there is just no mechanism that would protect the network from bad actors.