Capturing the face is always a challenge. Image Metrics Ltd. developed a tool which makes it possible to get facial motion without markers and make up on your rig. They capture the actor with a good resolution (it doesn't need to be high resolution, SD format works totally fine) video camera. Their software analyses this video and the moves of every part of the face and puts it on your rig. Even the eyes motion is transfered to the rig. The result is amazing real. You can take every kind of rig. It doesn't need to be a human head. You doesn't even need to use the whole face. The company did a commercial with a heart which is singing and they used the Image Metric technology to capture the mouth. Incredible result.
So far they don't sell their technology as software. So you have to send them your rig or order the rig in their house and you will get the complete animation back. But they are working on a software for selling. So, I think it's worth to have a look at their technology.