I have the Bamboo Fun... just the small one. It is the perfect size. I LOVE the pen and I got it to get rid of my mouse so I haven't even tried the mouse that came with it and never will.
I have a cyst on my right wrist and the pen puts far less strain on my wrist than my mouse did.
I love how I have a lot more control. I love that you don't have to drag the cursor across the screen. Your tablet surface corresponds to your screen, so to get to the other side of the screen you just put your pen there rather than dragging the cursor over.
There's nothing I hate about it! It rocks!
I didn't find it frustrating at all. It only took me a day to get used to.