Dark Wallet looks pretty good. Not many people using it though, so some transactions take awhile and very few are being mixed at this time. If no one is there to pair with the transaction is just sent without mixing. I'd prefer having an option to wait, even for days, until a matching transaction is available for mixing. A time out period should still be setable so funds won't get stuck indefinitely.
Also, if the transaction doesn't get mixed the only indication is a temporary comment at the top of the window. Otherwise, you need to go to a block explorer. I think we need some better indication in the Dark Wallet itself of which transactions were mixed and which were not, and how many different addresses where involved in the mixing.