No one. Collect data from many, cut out outliers and average it out. Same as any other review. With pastes the reviews can take time to be made though. There are decent pastes on market for years now, Noctua probably just playing catch up with their paste in terms of performance as the previous one from them wasn't anything spectacular.
As far as NT-H2 it's rather price competitive with Gelid GC extreme (claimed 8.5W/m-K) and Arctic MX-4 (claimed 8.5 W/m-K) so we'll see how it fares.
NT-H1 is quoted at 8.9W/m-K and Kryonaut is supposed to be 12.5W/m-K. Prolimatech PK-3 suggested thermal conductivity is 11.2 W/m-K , Cryorig cryo-paste CP5 is listed as 9.3 W/m-K (the often included CP-7 is listed as 8.3W/m-K), Be Quiet DC1 is stated at 7.5 W/m-K and Phanteks' PH-NDC is supposedly 4.5W/m-K.
I can neither accept or refute said results, but yeah, they do fall in line with what others have been saying; either way, it's not worth it for me anymore. It's a whole process applying that damn thing, its superiority in performance is misleading/not representative of reality (give it a couple of weeks and look at your temps again [yeah, they all do it, but it's a lot more prominent with Kryo]) and like you said, its pricing is.. a touch high, all things considered?
Oh speaking of performance, don't know if you've all seen this, but noctua actually give you the difference themselves, should have checked from the beginning, included it in the OP (my bad):
I have a tube of 9 year old MX2 that works just fine. Used it on my 1080Ti Aorus heatsink that I strapped 92mm fans too. At 2167 with 1.2V it stays right around 60°C at furmark load with the fans full bore.
I have a new tube of MX4 I used on my 7900x post delid and am quite happy with that too.
The alcohol injection site prep wipes at Rite Aid most likely work just as good as those for $6/box of 250.
For most people, paste is paste unless it's Elmers.
I usually use MX-2, MX-4 or Gelid GC Extreme. I have used Thermal Grizzly products in the past, but don't see the advantage in performance
Same boat more or less.. it's a necessary journey i guess, seeing and experimenting on your own; but ultimately, it really comes down to reliability and some semblance of trust. And copious amounts of time saved.. rather than wasted, lol
Less, or in this case fewer to be exact, turns out once again to be more