* The ability to have a global shortcut to activate it, and it hides nicely in the menu bar when you don't need it.
* The magnification loupe follows your cursor, so you don't have to keep swinging your head back and forth to see where you are.
* You can adjust the size of the loupe.
* You can set two formats for color copying, and use one with Cmd+C and the other with Cmd+Opt+C.
* It keeps a history of colors you've copied.
* It works properly when you screen zoom with Ctrl+Mousewheel.