I use the wacom Intuous 2 for sketchup - In general I recommend it -feels more precise than the mouse -
I keep the mouse plugged in as well for the combination of scroll wheel zoom with the orbit and pan tools (two handed operation)- so far I keep the side buttons set on right click (for the context menus) and alt (- to change the active tool back to select.)
I'd like to be able to pick up colors like in Photoshop by pressing the side button (alt) while clicking on a color - but this doesn't work in sketchup - (after selecting the paint bucket - alt on the keyboard picks up a color and releasing alt returns to paintbucket - not bad) By changing the shortcuts in sketchup and reprogramming the pen's side buttons there may be some combinations that make the pen work better
with sketchup - phil