As a recent buyer of the DS (Dec 2013), after three weeks of listening to my DarkStar, I can only echo a previous headfier who best said upfront "It just sounds 'right'" (I take this subjectively and objectively!). I agree with figaro69 too. This is some further feedback...
The DS gives a very instantly satisfying, +fulsome+, detailed, "balanced" sound to my ears (I listen to jazz and classical only), and while sounding great with my HD800, LCD3 and HE6, the marriage is only consummated with the HE6! My sources were HM901 and HM801: I depend on these and need portability. I admit I generally like the airiness and neutrality of HE6 even without this amp - I've use SR71b, BUDA, EF5 and 6 - but the DS, IMO, does indeed make it shine. (Of the others, I love my EF6 though, but DS outperforms and well it should at the price differential and looks).
I listened (more on HE6 and less on LCD3) to Eliane Elias' recent "I Thought About You; A Tribute To Chet Baker" CD: your hear her intimately upfront (HM901's Balanced Switch being ON) in front of you and the instrumentation is nicely panned and rendered (this recording is actually recorded well, a 'first' for EE with so many other recordings: lovely CD as is George Benson's orchestral crooner "A Tribute to Nat King Cole", same class). Kate Reid's superbly recorded and sung "Love I'm In" (also "Sentimental Mood"), little known but one of the very best classic contemporary jazz singers in a crop of young so-sos, comes off just brilliantly - timeless. Needless to say well recorded Sarah Vaughans or Anita O'Days are nice, albeit the recording quality varies. [Flicking to the non balanced switch on the HM901 pulls back the vocals and gives a wider soundstage or more prominence to the instruments on this setup and others.]
On instrumental CDs, Hank Jones "With the Meridian String Quartet", a gem, is feather-touch. Stan Getz/Kenny Barron club duets in "The Complete People Time Recordings" gave intimacy and clarity. The likes of Bobby Hutcherson and Mark Sherman on vibe recordings were good but maybe the carryovers are best left to loudspeakers. Some Ahmed Jamal recordings gave an almost surround sound feel and bass play on several jazz recordings come off distinctly and firmly (more so with LCD3+DS, somewhat predictably). Drumming by pianist Cuban Hilario Duran's bands ["El Negro"] in "From the Heart" was crackingly good and taunt...while clarinet/sax crescendos by Paquito D'Rivera in "Quartier Latin: Live" and delicate lyrical pianowork by Chano Dominguez "Flamenco Sketches" ... were very enjoyable, to me. 2L Mozart pieces from HDTracks at 88/24, 44/16 and 96/24 were rich, spritely and enjoyable, in this land of Mozart. Vienna New Year Concert pieces (assorted years and recordings) by the Vienna Philharmonic had that swing and verve and detail on the amp that is their trait; Strauss lives and puts one in upcoming ball mood nicely. Of course, I do give particular credit to HM901, my favourite player, plus little extra oomph to Moon cables also for a good part of these final renditions...
As between headphones, LCD3 +DS sounds very appealing to me on some recordings but just ok on others [some downright horrible and narrow soundstage too] - I presume this is very much a LCD3 signature trait. But LCD3 +DS gave by a good margin the most natural sound to my ears of these 3 headphones. HD800 sounded very full with the DS on most CDs I heard, with its characteristic acoustic distanced sound - to me the HE6+DS makes me much happier on more recordings even though it is also not a forgiving headphone. In some ways I find HE6 and LCD3 have more individual character than the HD800, despite its great status.
I am currently trying to decide on the best closed phone for the DS with lesser leakage/seepage and good clarity/neutrality/some brightness : TH900 (bit leaky I gather) being the hot runner given LCD-XC price and pros 'n cons ('thinner sound', heavier weight). T5p being a consideration but overpriced.
One thing which surprised me on receiving the DS is their size/weight : way smaller and more compact than I expected. This was practical - the photos of this amp kind of make it look falsely big, but they fit quite nicely on a bedside table. In comparison, my old EF6 is anchorweight. The only observation I have on the DS is that when I switch off, there is a subsequent loudish shutting-down click on my HE6 cans as the DS electronics go down (I switch the portable off first and then the amp...maybe I'm doing something wrong). Some slight hiss was heard on a few recordings, as some have observed, after the music died off, nothing which bothered me at all.
RS, while saying it takes 2-3 weeks to hand build and being a man of fewer words:), actually expedited my DS to Europe in much less time, kudos to him on this. It arrived fast, well packaged and suitably humble looking.
Overall, I am very happy indeed with the DarkStar which I bought after the many important comments by headfiers; I could be even more sublimely happier were it $1000 less but it is bearable for this lifetime though hopefully cheaper in the next...
Do you also hear the faint hiss as Nishy described with the sensitive headphones ? Can you confirm that ?
I think that issue should be fixed, this will delay my decision to order DarkStar :(