Been using those Amazon lights to walk Seren for the last couple of days.
They're OK. They don't have a reflector, so as you go from flood light to spotlight the beam changes from round to square (shape of the emitter). But, unlike the other similar flashlight I got a couple of years ago, the spotlight beams on these aren't well focused. They're... muddy. Still fairly bright.
I like the on-off switch. Those "72 presses of the end cap to get to the light output you want, and running past it several times" switches are annoying.
I would, however, find them to be a bit more useful if the on-off switch were on the barrel instead of the end cap. It's workable, but a bit annoying.
Construction seems to be sturdy. I'm not sure how much use the pocket clip is going to be. The lanyard is a bit on the small size and won't fit over my hand to go around my wrist. Those are minor issues, though.
All in all, not bad for $20.