Really? Well ones a full carbon wheel, one isn't. The spokes, theyre not integrated, you'll get water in them and then it swishes around till the drain hole works.
Really you get what you pay for. HED6s go for under 1k new and Reynolds 72s around 2k new. Also the obvious ,ones more aero than the other. I went from Hed6s to 72/90 Reynolds and bike split went from 5:45 to 5:13 on the same Ironman. Hed 6s are a great value but not as good as a full carbon wheel with integrated spokes. I think they're very similar to the Bontrager Aura 5s, another value wheel, same drain hole and aluminum brake surface. Bontrager has the Aeolus though so you can see the difference in upgrading to full carbon, not sure if HED has an equivalent yet.
Edit: did a quick search and HED Vanquish 6 is now they're full carbon wheel. They promote it that way too. The Vanquish 6 sounds more equivalent to a Reynolds aero 72
One's full carbon, the other isn't, so what? Are you under the impression that full carbon construction provides a meaningful performance benefit? Typically carbon wheels are a little lighter, but the material itself doesn't bestow an aerodynamic advantage and for rim brakes it generally incurs a braking disadvantage. It's highly debatable IMO whether full carbon rim brake wheels exist for any reason other than the willingness of cyclists to believe marketing nonsense, engage in group-think and worry about aesthetics. So, in summary, full carbon does not mean better.
Integrated spokes, by which I presume we're referring to nipples fastened to the carbon at inner radius of the rim rather than passing through a fairing to the alloy rim, mean relatively little as far as I'm concerned. I've got Swiss Side Hadrons which similarly are not sealed at the nipple and have a small drain hole in case of water ingress. It's never been a problem, and I've never heard anyone say they had a problem with it, and I've raced in torrential rain on roads with significant surface water. That simple drain hole is used rather than trying to seal the rim because it's simpler, lighter and it works.
Now, I concede, some people will argue the above points and any may insist braking is adequate with carbon or whatever. I disagree, but I've said what I think so lets move on to the big one.....
Apparently you think it's obvious that "ones more aero than the other"
and you're crediting the Reynolds with bestowing upon you a 32 minute improvement in an IM.
I'm afraid there can be only one description of this claim. And with all due respect, it's an entirely accurate appraisal. This is utter garbage!
Find ANYONE with a shred of credibility on ST to endorse that claim as being even vaguely possible. I challenge you. There are no two ways about it; it's just total nonsense. Claiming any data for individual changes by comparing events with a multitude of variables is silly, but I don't even need to make that argument since the scale of the benefit you're claiming is so ludicrous. Those times may be accurate but if you think wheel aerodynamics are responsible, you're wrong.
Some test data was provided above by others and there is plenty more elsewhere. From what I've seen, and to the best of my recollection, in the wind tunnel, the HED Jet 6s have repeatedly performed among the very best and often equal or outperform many far more expensive wheels. So I believe you are inaccurate to suggest cost is a reliable indicator of performance. Given the choice of top of HED Jets, or top of the range ENVE, Lightweight, Zipp, Reynolds, etc.... with money being no object, I'd happily use the Jets and not feel I'd made any significant sacrifice. Of course, if I was allowed resell them I'd take the Lightweights, sell them at once and buy HED Jets. ;)
I recommend both yourself and the OP have a look at the available test data on the HED Jet wheels to verify the above. I do have some issues with how wind tunnel and other aerodynamic testing and analysis is done in the cycling realm but it's a hell of a lot better than nothing, which is in turn better than misleading race time comparisons.