Bare's marketing department is a frickin' dumpster fire.
A good conductor is the opposite of a good insulator. To stay warm, wetsuits need to be a good insulator. And yet the Bare marketing department is shouting to the Heavens about how warm the Reactive suit is because it uses graphene and graphene is a great thermal conductor.
Fortunately, I think the graphene in the Reactive suit is truly ONLY a marketing thing. I don't think it makes any difference one way or the other in the suits.
I have a 3mm Reactive and also had a 5mm Reactive. And I have ScubaPro EverFlex 3/2, 5/4, and 7/5, and Waterproof W7 5mm. And a few other suits.
The graphene thing is just baloney. But, the Bare OmniRed lining could possibly be onto something.
I don't have any data to report. But, anecdotally, I feel like my Reactive suits have been the warmest suits I have used, in their respective thicknesses.
I have pretty much switched to my Waterproof W7 5mm for all my non-drysuit diving. But, that is because my shop sells Waterproof, the W7 has thigh pockets, and it is pretty close to as warm as the Reactive. That is also the reason I sold my Reactive 5mm - I no longer was using it.
For pure warmth, and whatever the "science" or "technology" behind it, the Reactive suits do seem to be the warmest suits I have tried.
If the Reactive 5mm had pockets like the W7 does, I'd be diving a Reactive.