I've got one, use it with the LASR software on my laptop. Works pretty well, but does give you a false sense of speed. My draws are like a rookie, but my bill drills and el prez drills say I'm a grand master or something. The lack of recoil, etc means you go way faster with the laser than you do in real life.
Mine did eventually fail, sent it back and they charged me some amount I can't recall to replace the trigger guts and now it's back to 100%.
Rob's right, you can leave it out on a workbench or whatever and there is no risk because it's not real (and it doesn't upset the wife that I might have left a gun just 'laying around'). Also super useful for training new shooters, they get to work on all sorts of things without fear and then find when they move to an actual pistol that it's all mostly the same and the skills transfer easily. Removing the fear part really, really helps when you're teaching people who are mostly... well not anti-gun just anti-gun-experienced. They don't know and that's what keeps them away.
All that said, if I had to do it again I might opt for the IR laser version. I don't like that my eye is drawn to the red dot during drills. Sight focused, dammit!