Unreliable as in noisy in a way that I could not fix with temporal averaging. I tried to guide a robot arm to pick up the top object in a bag of evenly colored objects, but RealSense gave me randomly fluctuating values and rather large undefined areas (areas that were blocked from the view of one of the two sensors). The ToF sensor gave solid values even outside when it was snowing. Of course the ToF sensor had other problems, high requirements for power and cooling, and perhaps worse performance in very strong sunlight.