Just got a Canon T4i recently, learning it, it has a feature to focus and track a model's face. Wondering if that is worth doing, or just an alleged feature that does not really work on a practical level? If it works, could be nice for shoots where the model might be moving about and striking different poses, especially if a low DOF.
I'm pretty sure that only works in live view mode.
I think you're going to have to try it and decide for yourself. The little bit that I've done it - always by accident, it's worked, but I hate shooting in live view, so my answer is that I don't consider it practical. I think however, that it works adequately well if you can tolerate live view.