Yes the Lumia 950 and 950 XL have had them for a good while now. It didn't work too well with those devices and accuracy was not great. Certainly a good distance away from a good fingerprint scanner
Main complaint from users & reviewers was that on a mobile it took far longer to unlock via this method than even inputting a pin.
You have to bring the phone up into your eye line, you have to wake screen and initiate the scan. You can't wear sun glasses or tinted glasses without issue.
The good finger print scanners like the S7/HTC 10/ Nexus 6p/ iPhone 6S etc.. You can have the device unlocked between picking it up and looking at the screen, which is far faster than the Iris scan method.
Some have said that it may work as a 'complimentary' unlock method for when you can not touch your device ? But then logically if you can't touch your device for whatever reason at the unlock stage, why would you be wanting to unlock it ? because as soon as you've done so, you will need to interact with it by touch regardless .. In which case a finger print would still be far more accurate.