I'm on my second Trek 7, and while I generally agree that they are well made flashlights, I do share some of Brock's long term usability concerns.
I've found that it's fairly easy to screw the head down too tightly when turning on the flashlight (especially if you lend the flashlight to someone who's not quite as gadget oriented as we are). This can, at a minimum, result in the bottom of the lowest C-cell battery becoming dented by the electrical contact. I shudder to think what damage to the circuit board might result over time.
I've also had major problems with the flashlight intermittently coming on even when the head is well backed off of the normal "on" position. This is now occurring even in my second Trek 7 which has only ever been used by me and has never had the head screwed down too tightly (my first suspicion as to the cause). It's really quite annoying as any movement of the flashlight with the head pointing upward results in constant on and off flashing of the light. Brock, have you experienced this problem and/or heard of any potential fixes?
All-in-all though, the flashlight puts out a good deal of light for an extreme amount of time, and does so in a relatively compact package.