I don't completely agree with the fact that mouse users will have an unfamiliar feeling when using a tablet. I mean just try to write your name in paintbrush with your mouse, that's pretty strange.

There are many 3D software that take advantage from a tablet, whatever you're an artist or not. Poly modeling for example will give you great benefit, from lasso selection to vertex pushing manipulation. More over with scuplting tool like in Silo, Modo. Without talking about Zbrush and Co where using a mouse is just impossible if you want to do serious work in. A little transition time is needed (especially because of the double click and menu navigation in general) , but at the end you will no use your mouse anymore ... well at least that's what appends for me :)