I have this on my current car (Mk3 Focus). It came as part of a driver assist pack with other bits.
I have actually switch mine off now. I found that depending on the road angle and sometimes from behind a vehicle the lights would not dim automatically, so giving the other driver Full Xenon beam.
But, the last time I used it and have since switched off, was when I had gave the full beam treatment to a Police traffic car. He was heading towards me where we both going into a steep dip in the road - my car sensor didnt pick up his lights for some reason, so went full beam

Another piece of great tech, which I don't think is perfect for all road conditions. The Focus has three settings of sensitivity, but tbh they all seem pretty similar to me. Also, found the lights would dip when sometimes heading towards road signs....