@david_ten I 've heard the M12, yes, only after I purchased my KDS/3, though. A good friend of mine is a Bricasti dealer and he offered me one well under retail. I thought it sounded very nice. The dual mono design really makes a difference.
What's ultimately enchanting about the KDS/3, however, is it's doing what Chord is doing in two different boxes, in one box + streamer, getting out of the USB path. At 16x RBCD, in the Linn and Chord FPGAs, in theory you're now closer to rendering 16-bit audio than ever before. In that respect, I don't give a hang about DSD, unless it's a unique mastering that was transferred to DXD then DSD. These are rare.
Anyway, I'm getting OT, but, you're probably right about the mini-Ulf. That is to say, if the DIs are all what they're cracked up to be, then the mini-Ulfs should be a no-brainer.
Like yourself, I have never made the jump to tubes.
And @grannyring like the Lyngdorf, Linn is largely overlooked this side of the pond. I've heard the 2170 and I thought it was a fantastic product that does a remarkable job.
I look forward to using Linn's Space Optimization on either the DI or the mini-Ulf, should one fit the bill. I mean, all of these voice in this thread, with so many different tastes in music, downstream gear, and experience can't be wrong.
One thing I've noticed, though, is that nobody has mentioned heavy mental of hip-hop with the DIs. Now, I'm not a metal head, nor do I listen to a bunch of hip-hop. I'm more of a classic rock, small ensemble chamber music, classic jazz, acoustic guitar, prog-rock music lover, but it isn't beyond me to put on some Metallica, Maiden and Beastie Boys from my youth. :-)