I use my Asus EP121 for 3D work constantly. Rhino, 3DCoat, Moi and a number of others. It performs well enough for most light to medium duty 3D tasks but I suppose that is all relative. If you end up with a EP121 for some reason you should take a look at the case I designed for it. Way better than the case that comes with.
Link
http://www.kickstarter.com/projects/821403096/flipsteady-for-ipad-2-and-the-new-ipad/posts/318799
Good luck in your search!
Isaiah Coberly