Okay, I've had a little more time to burn in the Music Streamer+ ($299 new) as well as do some critical listening of it versus my stock PS Audio DLIII ($699 new).
Overall, I'd say the HRT is very impressive, but I don't know that I would take it over my DLIII - that said, I think the HRT beats the PS Audio in a few key ways, and the DACs generally play on even footing - depending on your musical tastes, you may find the strengths of the HRT more appealing than those of the DLIII.
I'd say that the main story is that the PS Audio is a more refined and "technically sound" DAC, if you will (though still imperfect in a number of regards). The soundstage feels large with a very black background, the bass is full and crisp, and everything sounds very detailed. By contrast, the HRT is a shade behind in most of those regards, but it has a slightly sweeter and more euphonic midrange.
My first two test tracks were purely instrumental - "No Messin'" by Acoustic Alchemy and "Within Attraction" from Yanni's Acropolis concert. Through both of these tracks, I found myself liking the DLIII more - it was slightly more exciting and dynamic sound, with crisp attacks and decays and deep, full, and punchy bass. The only mild dislike I had here was that the DLIII could get slightly piercing in the treble and sound tipped-up on occasion.
The HRT, by contrast, had a slightly more forward presentation that tended to blur the sound slightly. Keep in mind that this is intended to capture a very slight difference between the two - don't read this and think that the HRT sounds blurred and incomprehensible. But the crispness of the DLIII, the punchiness (and a little bit of the impact) of the bass, and the stark black background were just not quite there with the Music Streamer+.
I was a little disappointed by this point because I had expected the Music Streamer+ to get in a few punches on the DLIII based on the reviews I had read so far.
I then switched over to a couple of vocal tracks - "Please Don't Be Sad" by Youn Sun Nah and "Na Osicce" by George Mraz. Both are female jazz vocalists, although the styles are slightly different. It was here that I heard the starkest contrasts between the DACs. Every time a woman's voice kicked in, the Music Streamer+ sounded extremely lush and musical. The ladies' voices sounded smoother, fuller and sweeter. This is where the technically competent DLIII fell a little short - through the PS Audio, the voices sounded a touch thin and mildly grainy relative to the Music Streamer+.
I also tried them briefly with a less well-recorded track - "A Thread Cut with a Carving Knife" by Stars. As expected, the Music Streamer+ was a little more forgiving and didn't expose the recording's flaws as brutally through my K701 as the DLIII.
If all I did was listen to vocalists, it would be a no-brainer for me - I would keep the Music Streamer+. Unfortunately, I actually tend to listen to more instrumental music than anything else, so the HRT probably won't stay in my stable for long. But for someone whose musical tastes are more closely suited to what I've described as the HRT's strengths (vocals, pop, etc.), I think the Music Streamer+ is likely to be a very attractive option, especially at its price point.