Face detection in OpenCV and its related haar detectors are all very good, but if you want to be reliable and practical, you still have to train yourself.
The companies with the best face recognition are FRVT in 2007 (NV acquired by Google participated in this year, with the first comprehensive performance) and MBE in 10 (pittpatt acquired by Google participated in this year, with average performance, but their face detection and pose estimation seem to be very good, and cmu has many patents).