FaceRig is only in early access now, so it does have some flaws, but overall, it's truly awesome. It is professionally made face-tracking software that works just by analyzing your face through your webcam, for a ridiculously low price. It's great for literally anything for which you can use your own face, like Skype, vlogs, livestreams, or to keep your anonymity on infamous websites like Omegle and Chatroulette.
What is truly amazing about this is that normally, to achieve the same results as FaceRig achieves, you will need to have either a special suit on or to stick your face full of tracking orbs. FaceRig just analyzes your face through the webcam, and measures all the points of it without all these expensive Hollywood thingos.
The flaws are minor ones, like if you have a bad webcam, the program will likely not work as you would expect. If your face is blurry, it won't be able to recognize you. The same problem occurs when you move too fast, but that is the same reason.
Sometimes, frowning doesn't completely work, but with the reactions on your friends' faces, I doubt you would ever frown anyway.
Things I'm looking forward to: Movement of the arms. If I can have that in here, FaceRig is just perfect.