I have an IQ-XS on a couple bikes. Cheaper than the IQ-X and has a metal housing, but not as bright a beam. The less bright beam is good enough for me. They make two versions of the IQ-XS, I wanted the version with metal housing, the other is not metal. When I bought mine, they were rated at 70 lux, now rated at 80. Not sure if they changed the innards, or if they just re-rated it.
I have one on my rando bike, first photo, I used an extra long Edelux mount and bent it to be straighter to put the light higher. I did not use the fork crown for mounting, that is already in use for my brake cable hanger. That is why I mounted it on my canti brake post.
I had an IQ-XS on my road bike, used an optional B&M mount for that, second photo. But I moved that IQ-XS to my light touring bike after the photo was taken to use for my last tour.
The IQ-XS has been on a few times when I thought I had turned it off. Not sure if it came on by itself or if it was user error on my part. I am not sure about this but I think it is possible that it will come on automatically if the capacitor for the stand light is empty, as then the electronics might have forgotten if it was turned on or off. On my tour, it usually stayed off in the morning when I started riding if it had been off during the prior day, but in this case the stand light capacitor was still charged. I am not sure if the stand light capacitor will charge from the hub when the light is turned off or not.
The reason I want to turn it off at times is that I might want to use my USB charger instead to charge batteries, thus want the light off for more power for batteries. Both bikes where I have an IQ-XS, I also have a USB charger wired into the circuit.