My new lights are here!
Not got time to put together a full review with pics yet, but a quick summary and comparison with the iTP A3 Eos:
Trustfire XP-EF23: Hi/lo/strobe, hi mode very similar brightness to iTP A3 Eos's hi, slightly colder tint and a little more tightly focused. Quite heavy, about 1" longer than the A3 and maybe 1.5mm thicker, VERY nice shiny finish, feels built to last. No problems and no adjustments/modifications required.
Black Cat HM-01: single-mode, a little dimmer than A3's Hi mode, brighter than A3 in Med, much tighter focus (surprisingly good thrower!), tint a little warmer. Very light, similar diameter to the head end of the A3, about half an inch longer, grippy but slightly rough knurling at head and tail, pinkish-red anodizing, feels robust despite light weight. No problems and no adjustments/modifications required.
Unbranded DX $3.42 AAA "3W" light: single mode, a little dimmer than A3 in med, bluish tint, very floody beam without much of a hotspot. As expected, if this produces 3 watts then I'm a monkeys uncle. The LED emitter is some sort of 5mm variety but with more output than most 5mm types; surprisingly for this price it looks to have something like a "proper" driver board. About 3mm thicker than the head of the A3 and about 1cm longer, VERY thick battery tube, heavier than the Black Cat and iTP, knurling on head but not very grippy, cheap-looking bare ally tailcap, twisty switch means it's a "battery crusher" - I had to remove the tailcap spring and file down the inner side of the tailcap to make it work. (That said, bearing in mind the ridiculously low price, it's something of a bargain)
Unbranded DX 3xAAA flood-to-throw zooming "100-lumen" light: 3-mode (hi/lo/strobe), adjusts from very floody to very tight throw (beam shows shape of LED die when at full throw), similar output on hi to an Akoray K-106 (will use this for comparison as its a bit mismatched to the iTP!)on hi, slightly warmer tint. Body quite chunky - head about 1.5" diameter, overall length about 1/2" longer than the Akoray, neat but not particularly scratch-resistant black finish. Initially the head (which screws in/out to adjust zoom) felt very loose - threads are loose and original O-rings too thin. Much improved by fitting slightly thicker O-rings although threads still loose and a little rough.