For someone who's been making nothing but broken polys and stickman out of primates, this is a huge step up.
Practically the first 3D model ever (discounting all the teapots).
Mudbox has to be the easiest 3D program I ever used - and I've used all. 3DS Max, Softimage, Maya, Lightwave, Poser 4D, zBrush, Blender, etc etc. I've never gotten past the 'zoom in, and rotate to change view' stage.
I found Mudbox to be incredibly easy, well firstly due to simplicity of the program. The program doesn't have nearly as many function as any other programs around. And secondly due to the fact that the UI is very simple and Photoshop-esque. If you're a Photoshop junkie like me, you won't have much problem with it.
p.s. I think I finally get zbrush too now that I think about it... lol. gonna give that a try now.