the class of compact coolers being Mini Ninja, Xigmatek SD964, Samurai ZZ, Big Shuriken, Samuel 17, Gelid Silent Spirit
Apart you're just boringly repeating too much times the very same words (we have understood your point, trust me), take note that even if I said I wouldn't have repeated myself, that doesn't mean that I would let such a silliness pass freely.
An homogeneous "class of compact coolers" as you instantiate simply doesn't exist (neither SPCR ever dreamed to define so your spurious gloss): not even by mistake a "Minja" or an SD-964 would ever be in the same league of a Scythe Big Shuriken (and as a matter of fact they cools better, and they are twice or three times taller than this latter). And if it's not homogeneous, it can't be a "class" (the chart on SPCR has mostly an historical reason, the coolers which fit inside the NSK2480/Fusion which MikeC engineered along with Antec, IIRC). And if there isn't such your "class", the Big Shuriken can't be its "top-dog".
Or do you want to argue that a Noctua NH-C14 is a Shuriken par, because it can be 6mm shorter than a Minja? Please be gentle, make my day.
But the Shuriken or the Big Shuriken are both just so difficult to mount they just aren't worth it regardless of their performance, in my opinion. In addition, specifically on the Zotac, you actually have to remove, then remount, the other heat sink to squeeze the Big Shuriken in and there is still some interference between one of the Big Shuriken's feet and another Zotac component. How you properly remount the other heatsink, once you have the Big Shuriken mounted... beats me. But people have done it. One big headache.
Personally if I am ever using a case where the Shuriken or the Big Shuriken are the only options, (and the slightly taller Geminii won't fit) I will just find another case.
As I've already said, a really small case as the Antec ISK 300/310 is a trade off personally I wouldn't afford.
That said, I agree that stock mounting system has ever been the Achille's heel of any Scythe's cooler (with some noticeably exceptions).
But it's just a surmountable (pun not intended) drawback: the Big Shuriken just need a SCURK 3000 kit to be ok on an Intel platform (on AMD platforms the stock mounting system is still infamous but works really well).
Another, different issue it's the Zotac boards: it would look like that you simply haven't completely done your homework, IMVHO.
IMO Zotac is one of the less effective choice in a quietness perspective: a dull BIOS, no real possibilities to effectively control its headers with SpeedFan (or under Linux with fancontrol, IME), paired with the 2300rpm fan of the original Shuriken it's likely to be half a nightmare (while that fan is inaudible under 1000rpm and still able to run a pair of instances of Prime95 with safe temps).
Add a more probably that not somewhat poor socket placement and the board small form factor, pair those elements with a cramped enclosure (or you wouldn't have need a Shuriken, I guess), and you are likely to have a though, disappointing combination for a silencer.
Anyway, there isn't just the two Shurikens to work in tighty spaces: there's at least also the Nexus LOW-7000 R2, probably the real "top-dog" with reference to the quoted SPCR roundup (unfortunately it's rather uncommon and often expensive, besides be a bit taller), and in some cases the Thermalright AXP-140. And probably even some other else.