One problem with using graphic tablets is found in trying to coordinate the movement of your hand with the action on the screen. With a mouse it is generally easier to coordinate your movement (in part because of it's limited range of movement to begin with and in part because the action is carried out with the shoulder rather than the wrist) with the action on the screen. Of course, with practice this becomes easier. An alternative is to use a graphics tablet that actually has its own built in screen. This gives digital graphics artists the same kind of immediate visual feedback they receive with traditional tools and media.