CoinJoins algorithm suffers from not being atomic and thus it can be repeatedly jammed by an adversary, i.e. denial-of-service. This is because first the inputs have to be collected, then the outputs have to blind signed with a group signature, and then finally all inputs have to signed. If any one of the participant senders fails to complete all the steps, the transaction is jammed and the process must start again. All proposals for throttling or blacklisting adversaries was argued to be ineffective and intractable. Darkcoin innovated CoinJoin by adding a collateral payment which is forfeited by participants who fail to complete all steps. This requires a random master node to break the unlinkability as it knows the matching output of each input. It is assumed that not all master nodes will be adversaries and thus sending multiple times through different master nodes will provide a probablistic level of unlinkability. The master nodes are purchased and it isnt clear that a sufficiently powerful adversary couldn't sufficiently Sybil attack by acquiring a larger percentage of the master nodes. There is also concern this might also enable the adversary to steal collateral payments. Also the master nodes arent untraceable and thus could perhaps be held liable by governments for breaking AML and KYC laws. CoinJoin and Darkcoin suffer from the simultaneity timing problem that other spenders need to send spends of the same amount simultaneously. -gmaxwell
Gmaxwell also shows that while Darkcoin have "advanced" coinjoin, it still suffers from the same issues, not to mention the Masternode centralization problem.
Darkcoin's anonymity is simply put, Trivial and Inferior to Cryptonote anonymity.
"There is also concern this might also enable the adversary to steal collateral payments"Badly behaving nodes are banned by the network."master nodes arent untraceable"Doesn't monero have nodes? Yes? Are they untraceable?"other spenders need to send spends of the same amount simultaneously"It's all automatic, users don't have to worry about that. User clicks send, and Darksend will wait until there are sufficient sends in the pool. And after the Darksend becomes mandatory (or default option) this won't be a problem as there will be a lot of people actually using the coin and creating transactions, as the coin can actually handle > 5 transactions per block."Masternode centralization problem"Doesn't monero have nodes? Yes? => "centralization problem"And, the most important thing - Darkcoin has a dev who is committed to developing Darkcoin further full time for 2 years still. So improvements are coming with every release.