I've got one. They're well made, and one of the brightest one-LED lights. They have a tailcap intermittant and twist for continuous on switch; the intermittant requires a bit of pressure. They are also a little long to fit in a shirt pocket (like a pen), but it's doable, depending on how deep the pocket is. They look great, BTW.
Main disadvantage: they take AAAA batteries (that's quadruple As), which are harder to find.
You might get more responses on the LED forum...