Hi.
What you are referring to is the Export Rigs as Shapes method:
The Animation Rig Export tool lets you capture all the animated deformations of the face as shapes and put them into a simpler rig.
I don’t think this is a good solution if your face is high res but if you need to continue to have some basic facial control in Maya, then it's ok.
Also, “Game Export Workflow”
That is only good if your goal is a simplified result like for a game, for instance.
What you export here is not the actual FR rig but a much simplified version designed to work with a low res version of the head mesh.
Manny Papamanos
StingRay | MotionBuilder | Maya | Mudbox
Games QA Specialist