I think Darkcoin is the winner. I took a look at CryptoNote and I think you can't tell the source of payment but the destination is clearly visible, correct me if I am wrong. With Darkcoin, you can't tell anything.
Hopefully after open-source more developers will join Darkcoin. Evan is overworking.
I started Darksend mixing 2 days ago: 3DRK, 8rounds.
And it is not finished yet: "Submitted to masternode, waiting in queue". - "Darksend is idle."
If it is not my particular bug - Darkcoin still has a lot to improve before general users can easily use it with satisfaction...