to answer the op's question...

Darkcoin's darksend is the clear winner on this front IF this is your only concern.

This is coming from a bitshares guy.


Now if you want to throw other things into the mix like market pegged assets backed by collateral.

The ability to self fund via 100% paid delegates(should also mention that share supply is effectively still hard capped via block reward halving).  

A platform that gives you the freedom to move from cny,usd,gold,silver,bitcoin all while earning interest.Never mind trading features like shorting.

10 sec block times with a avg confirmation time of 5 sec https://bitsharesblocks.com/ or crowd funding options via user issued assets.



But yes as it sits today Darkcoin is more anonymous imho.