The OpenBR API is designed to cater to the researchers and users of biometric algorithms, where as the OpenCV API is designed to solve a more general scope of image processing problems.

OpenCV includes implementations of several seminal face recognition algorithms (PCA, LDA, & LBP). The OpenBR algorithm is more modern/sophisticated in its combination of several well studied approaches. While I haven't explicitly compared OpenCV against OpenBR, the OpenCV algorithms can and have been expressed within the OpenBR and are known to be less accurate. Having said that, accuracy & algorithm choice are highly dependent on image quality. Our technical paper [1] provides more details.

[1] http://openbiometrics.org/publications/klontz2013open.pdf

OpenCV is about tinkering with your future career. With OpenBR you should open that beer and see where it gets you.

From the OpenBR website:

"Internally the code base uses the CMake build system and requires Qt and OpenCV."