I have a Graphire4. I remember it having a bit of a learning curve. I think the hardest thing to get used to was that every point on the tablet corresponds to a point on the screen, so that if you're trying to move the pointer, it lands wherever you put the pen down. Not at all like moving a mouse, which you can pick up and set down in a different spot and not have the cursor move.
Its been a while since I've used mine, so I'm sure that if I picked it up now, I'd definitely have to get used to it again.
The tablet is amazing to use with photoshop, though. I can draw almost just as I can with pencil and paper.