Importing OBJs is a pain.
First, it takes forever. The more edges and verts that need to be converted so splines and CPs, the longer it will take. Sometimes, it takes so long, you'd swear the computer was locked up.
Second, the result will require reworking. The splines that get created will not be laid out in the continuous fashion that creates smooth models in AM. You'll have to figure out how to reconfigure them so that you can keep the shape, and also keep the splines laid out correctly.
Third, materials will get messed up when you do all this reworking.
You are better of importing it as a prop, but only if you don't need to change it at all and can live with simple transform animation.
If you need to animate it with bones, make good rotoscopes of the OBJ in it's original program and use those to rebuild the model from scratch.