* 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.
I think $5.50 is overkill for a system utility with some trivial extra shortcuts and visual enhancements.
EDIT: re #3, you can change the magnification of the loupe, not its literal size on the screen.
As for the others, #2 is probably the most important of all for me, and would be hard to hack on top.
Even if it were possible, my time is worth more than $10 an hour, so I'll spend $5 to avoid a half hour of work hacking together some Applescripts.
Re: the loupe, yeah not sure exactly what you meant, but you can also change the magnification in DCM prefs.