Yeah, from what you're saying, I'm gunna agree with the Acurus Act 3 choice. I've owned 4 of these over the years (don't ask why I sold em...it's complicated -lol). I've also had Macintosh pieces, Aragon Soundstage, "updraded" Act 3, Sony's 9ES pre, and the Krell 5.1 HTS. And, even though other more expensive pre's are "quieter" (you mentioned hiss - which the act 3 has a bit higher noise floor than others, but not manageable, IMO - and I've had 'em in small, quite rooms) for the money, the sound is powerful, clear, detailed, dynamic, and pretty musical! There's better, yes. But, for much more. And, for your needs, I think it might be a good fit.
But, you sound like you might be a bit more finnicky than some. In which case, your tastes/priorities will vary.
The Krell HTS, is as clean, detailed (for 20bit), and refined as ANY 5.1 pre'pro you'll ever find, period! Although there's NOTHING more dynamic than the Act 3!!!!
The modified version is a lot more (if you can find one, which I've owned) - which is richer sounding, more detailed, and just as dynamic! But, for like $300 range, you can get very acceptable (MUCH more dynamic, uncolored, nicely detailed digital 20bit sound).
System dependency always matters though. So tastes and systems might vary.
As for NAD, I'd check quality control, otherwise nice sounding, overall. The Rotel is dynamic, slightly recessed on top, a tad bland, but otherwise descent enough sounding.
The Anthem is descent, but I think it sounds a bit like the B&K, kinda warmish, not as dynamic, but fairly good balance, I think. The inteegra?..no experience.
The marantz AV9000, I've sold and installed before. It's, like the Rotel - descent.
What you won't get with these pre's are the new DSP room correction however. And, knowing nothing of your room, that could be very useful, so consider. In a perfect acoustical space, you wouldn't bother.