I would recommend HRT music streamer II/II+. I have auditioned crack + MS II+ on a friend's place, and it just sounded awesome! I was hearing details that I didn't know were there in the music, and bass was tight and punchy, although not sure how much is that due to the DAC and not the crack itself. Plugging the crack directly to my laptop's headphone out, one thing really obvious is that now I can hear noise ('hiss') pretty loudly. It was dead silent with the MSII+, even with the crack volume cranked all the way up.
I should add, I have no other DAC to compare against (except the onboard sound card from my laptop), and the crack was speedballed (which might or might not explain the super tight, deep, and punchy bass).