"So - if I wanted to make one of the Transformers from the movie - your description makes it sound like NURBS would actually be the only way to go for speed and accuracy..."

It can sound that way but not all the time for mechanical models. The transformers are all sub-d models as is this one I made in Amapi 8 after watching the movie. One thing that counters the percieved need for NURBS if it is mechanical is if the accuracy is really needed for the "thing". If it is just to convey an image instead of prototype work then maybe not.

Allot of individual parts for a transformer will need to be tesselated and while MOI has one of the best OBJ exporters I've ever seen it's still not as good as a built by hand sub-d model as far as putting only the exact polys you need on the mesh in the first place.