I bought the KECES DA-131 mk2 about 2-3 months ago, second hand. It's a solid performer, doesnt put a foot wrong anywhere. Capable of big and clean sound staging, no rough edges, tight bass that is in the pocket, nice highs.
Having lived with a Killerdac for quite awhile, this dac went back in on a weekly basis as a sanity check. It doesnt capture that magical musicality of the killer, but play back killer recordings, and you still get that cheesy grin.
If you're on a budget and cant afford a killerdac, this one is very good. Capable of playing back hi-res up to 24/192, if that is of interest?
http://www.audiocircle.com/index.php?topic=64406.0edit: the output impedance of this dac is measured at 150 ohms.