RE: Raiblocks analysis in detail
No sybil attack protection. No spam protection. PoW is a fee in time and cost. But it's not scaling thus not enough to prevent sybil attacks meaning it's completely open. Its distribution used captcha method that was attacked as, once again, it doesn't offer sybil protection given ai and captch farms cost almost nothing. It uses delegation of stake instead of approval voting dpos have switched to because 1 account 1 vote is worst possible design method for representatives. it has same exact scaling issues as iota and blockchains by having to keep up with entire state of chain.
Bitcoin is important because it's secure. Steem tries to be secure by providing incentives and making it expensive and difficult to attack. RaiBlocks doesn't even pay its security nodes anything unlike miners or witnesses in steem meaning they have no reason to be honest at all. It's literally just badly copied old version of dpos with no incentives and a dag on top adding issues where they didn't have to be.
also, devs controlling most producing nodes is not a surprise. https://www.bitcoinbeginner.com/blog/raiblocks-needs-proof-of-stake/ but expected since there's no reward for doing all that work.
You make some fair points. As far as Sybil attacks go, an entity could create hundreds of RaiBlocks nodes on a single machine; however, since the voting system is weighted based on account balance, adding extra nodes in to the network will not gain an attacker extra votes. Therefore there is no advantage to be gained via a Sybil attack. As for spam protection, in the article you'll notice that it mentions there is a minimal PoW in order to prevent this. Moving on, when I spoke to the devs, I asked them about the incentives for running a full node. Considering they're evangelists they believe that people will set up their own nodes to strengthen an open system, which has been happening. Exchanges also have to set up their own full nodes. I believe that these are very minor flaws that are currently being dealt with as it becomes more adopted by the community at large.
https://github.com/clemahieu/raiblocks/wiki/Attacks