Months ago I thought it was impractical because of the button cells. That was until I saw one in operation. I can't think of another single 5mm LED light that is close to it in brightness. It is a screamer. I think that it's because not only is it overdriven, but the head and reflector make a huge difference.
I can't comment on run time, because I haven't played with mine enough to know, but I think that it's substantially better than I would have imagined. If we have a rain day tomorrow (Friday) and I don't get to work, I'll try to remember to do a visual run time test. If you decide to get one, you definately need to buy cells in bulk, not from a retail store. Battery Station had them for $3 for 10 and if Wit's End does another group buy on the light sticks, you can get them from him for 5-10¢ each.