As an artist, I've always been completely annoyed trying to do any art with a brick ( mouse ) on a computer.
( it's LAME! )
I've got an old wacom at home here and one at work.
They're not all that, but they are much closer to a pen/pencil/brush than a mouse is.
Using a stylus is much better for your hand/fingers/forearm.
A mouse can mess you up if you use it heavily day-in day out ( think editing alot of nodes, for example ).
And a stylus gives you better control.
.02