My boss killed his within the first couple days. Re-read the thread.
I ended up sending the dead diode to Spiderz since he said he might be able to repair it, or at least take some high res macro shots of it.. He hasn't got back to me yet.
Looking back, I think what might have caused it is that some of the driver's wiring was exposed, and it may have touched the case, though he did say he left it on for five solid minutes then turned it on and off rapidly. In either case, the one I built for myself is still holding up fine. I've left it on for as much as two minutes, though I usually keep the duty cycle under a minute.