In case you missed it, USA Today's Lee Neikirk posted a great piece this week that helps to demystify HDR. It's worth a read- he deploys some excellent real world examples (including a reference to a 2012 piece we did on the color saturation of NFL jerseys) HDR's promise of "better pixels" is much more than a "hollow marketing catchphrase."
Not only do HDR TVs boast more "saturated" (read: colorful) colors, they can also produce more colors... It's a gigantic difference, and means content creators and mastering processes have a much, much bigger pool of potential colors to work with. It also means "enough" color for something as granular as 4K resolution...
This expanded color granularity means subtler "steps" between colors as they travel from the dimmest to the brightest iteration. This means that even when employing much more saturated colors—like with Coca-Cola red, or say, the orange hue of the Denver Broncos' jerseys—HDR TVs are still capable of a subdued, realistic colorimetry.
"Better pixels" is all about "better color."