I used Windows Hello for about a year with a Razer Stargazer (IR Camera) and was always impressed with how quickly it was able to auth me, no matter if I was wearing glasses or not. Less than a second for me too, and that camera does not have the fastest start time, from camera init to capturing from both RGB and IR cameras.

At first I was skeptical about the usefulness of such a feature given my password doesn't take long to type, but it turned it to be a feature I really enjoyed.