I think that the 3D stuff has potential and will hopefully be perfected in a future edition of Photoshop.  The most useful thing it would have been good for is painting texture maps and previewing them.  As it is you can modify existing maps, but you can generate a UV map from scratch and create a texture from the ground up.  

As it stands now, the 3D import may be good for low res web animations or compositing 3D elements into pictures, but I'm sure it would take a lot of tweaking to get it into something that looks really cool.  Here is an example of something I did with a photograph and some 3D birds:

http://www.renderosity.com/mod/gallery/index.php?image_id=1433422

Had I been able to evaluate the software first and learn what it's limitations were I probably would have just gone with the regular Photoshop.  Generally speaking I was dissapointed.