That's really good to hear! The face tracker was one of the first modules to be implemented on tracking.js and, back then, we found Viola-Jones to be the most promising algorithm to make face detection (besides being the one used by our main reference, OpenCV). The whole library was refactored for this release, but we didn't change the algorithm and perhaps it is already out of date. We would be grateful if you could help us by sending papers about better algorithms (and reference implementations?).