We bought a Nolah mattress a few weeks ago, partly because one of its selling points is that it's "made without the heat-trapping viscoelastic chemicals used in memory foam."
I'm still not entirely sure what differentiates its material -- which it calls Air Foam -- from memory foam, because it feels very similar to other memory-foam mattresses. And the website doesn't do a very good job of explaining precisely how the materials differ.
It hasn't seemed any warmer than our old spring mattress, though, so I guess its "100% temperature neutral" claim holds up.
But as OP's post points out, the mattress review sites are very little help. It seems like they're all affiliate-link driven. I spent a good long while trying to find a review site that seemed trustworthy and that didn't make its money through referral links, and I finally gave up and decided I'd just have to try my best to evaluate each company's claims on my own.
Speaking of referral codes, it seems as if for Nolah, there's an almost constant $100 off code that is advertised on the site itself. Nolah also runs a customer referral program, where if you use my referral code, you get $75 off and I get $100 for the referral. Which is crazy. Why would you ever choose the $75 discount instead of the $100 discount? It's almost like you have to be willing to screw your friends over to participate.
That said, if anybody wants to PM me and obtain my $75 referral code, I will be donating any proceeds to the Trappist Caskets Child Fund, which provides caskets free of charge to families who have to bury a child: https://trappistcaskets.com/child-fund/