First-off, thanks everyone for the great posts, they were quite helpful as I dove in to commit to my first serious IEM/DAC/AMP setup. I'm an audio engineer (speaker and sub designer), and a regular on AVS and HDD forums, but am relatively new to being OCD around my IEMs. And it's all your fault, really.
However, I've got the bug.... After biting my nails about D12 vs. the RSA Predator, I went with this and must say I'm delighted. I ordered my unit Monday morning it's already here. Fit and finish is quite good, though there's a little more gap around the jacks than there should be.
I'm running it off a MacBook Pro using optical, driving my trusty Shure 530s (the JHA 16Pros should be here in week...). Playing some nice 24/96 flac files, and very impressive how much air, stage and depth this little gem projects. The background is absolutely silent, the music emerges from "black space" and the inter-transient detailing is superb. I can hear the rosin on the bows, people turning their pages on the scores, a tremendous sense of depth and reverb in the performance hall. I have to say, I have a lot more respect for the 530's resolution and top-end than I did off the iPod/Mac analog. I had NO idea they were this good, and am drooling waiting for the JHAs.
Only two complaints: the D12 needs a lower-gain switch mode and the volume pot could be better. At 10 o'clock it's as loud as I want, and audio only starts to come on at 9. Worse, when audio starts, the two channels are clearly not tracking very closely until moderate volume. As I seldom listen at low levels this isn't a huge problem, but a little more precision in this pot combined with a 1x gain mode would be quite nice. The RSA Predator beats this unit out, with Ray's attention to selecting pots that track well, and a three-stage gain selector.
My next upgrade may be to use the D12 DAC to drive the 16s via a RSA Protector, which ought to pair well with the D12 as the DAC, or to upgrade to a fully balanced iBasso config.
For the money: 5 stars