Just to show how personal preference plays into this, I like the US for many of the reasons that Al doesn't.
1) I like how slim the body is, and prefer it to a shorter bulkier one. Feels better in my hand, and points more naturally. "Bulky" is relative, I suppose, as I'm a size 9, not 15 /ubbthreads/images/graemlins/smile.gif
2) I like the switch where it is, being accustomed to a regular Stinger, and a 3D Mag that I had for 10+ years before discovering the newer and better stuff available.
3) No argument that more aggressive knurling would be nice.
4) No problem with the charger on my end. I charge it overnight-it's charged. A green light (go!) would be nice, though.
5) I love the ability to defocus the beam. Not for flood, but because I can take it from a tiny spot that throws and throws, to a wider one that still lights up objects a couple of hundred yards away, and lights up a larger area than when set on the tightest spot.
I also like the ready availability of batteries, bulbs, etc, and can order them online, or buy them at many places locally if I need them "right now".
I don't have a Tigerlight, MagCharger, or other similar light, so can't compare them, but I can tell you that I like my UltraStinger, and that I'm very satisfied with it.