[alvarosm]

Pre-processing and alignment are going to be way off. Even if it wasn't, then you have (for face recognition itself) eigenfaces or fisherfaces (bad) or maybe LBP(maybe barely acceptable). Your performance is going to be abysmal compared to serious face recognition technology.

[trapperkeeper79]

My experience is that OpenCV face detection works relatively well if you are facing the camera directly. We used an opensource face rec built on top of it, and it was okay to classify between a small number of known faces.

I saw some demos of M$FT's apis at a recent tech event and it wasn't obvious that the results with their system were significantly better. The biggest hole seemed to be that camera frames were being sent to the cloud, and there were issues with the presenter's quota (forget the exact problem).

But overall, I think the Cognitive Services are a step in the right direction. They generally make sense for businesses who don't have a full-time team of ML/CV experts.