jbrady85: I have seen posters say that balls do not affect putting
This is not quite true. The only thing which is not affected by balls or putters is the nominal length of the putt. I.e., x % on an y scale will always travel x*y feet.
In difference from the Starter balls, all custom balls will
a) provide a slower meter, and
b) have better precision. That is, you will hit or miss the cup more precisely ;)
(edited)