I hung around the HASH booth at SIGGRAPH for a while, and watched a couple of demos. Animation Master uses their own brand of spline patches (analogous to Rhino NURBS surfaces, I think), which they claim are better than everyone else's. My impression was that AM is a cool product, especially for the price (it was $175 at SIGGRAPH), but it's not designed to be used in conjunction with other products. For example, it can import polygon meshes with four-sided facets only, and each facet is translated into a single spline patch, which would not be practical for complex meshes. The export capability may be more versatile. I haven't used AM myself, so I may be wrong in some of these details.