It's a bit clunky and it's still directed toward developers using HTML colors. But it's a nice little addition to the color picker collection. It reminds me of the old/discontinued Pantone color picker.
NOTE that this version is a FREE update if you already have Developer Color Tool. The Mac App Store app it will simply say "Update'. The app will be found in your Applications folder inside a 'Color Picker' folder. This is unusual, but prevents collision with the 'Color Picker' app from Patrick Chamelo @nsCoding.