I have limited experience with tablets, but I know that my hand is steadier with the mouse. That's about it, but sometimes that's enough to choose to use the mouse over a tablet.
I was in an electronics shop and saw one of those expensive ones where you draw directly on your monitor. I think I would like that full experience someday. Cintiq or something (saw it a while back).
For the price I'm still putting my cash into other things like software, hard drives and good monitors, not to mention the computer itself. Were I painting and drawing a lot, I could perhaps go that route.
Meanwhile my cheap little graphire serves me if I want to get some of the calligraphic effects. I just one day got sick of constantly throwing money at my computer, even if it's a good tax write off, and said "this is good enough" It was state of the art a few short years ago and it still delivers beautifully (knock on wood). My hand, my mind and my eye are what it's really about anyway.
Personal opinion only. Hardware geeks will disagree, no doubt.
And in a way I'm with them. I can still go all gushy inside over new technology. I admire it greatly. But I'm sick of the expense.
"Not a bit is wasted and the best is yet to come. . ." -- remembered from a dream