I have a GLOCK light that I bought to use on my G34. It is as bright as any of the others (streamlight, surefire). It is very light, as it is all plastic, but may not be as durable. Mine has held up very well. I recently attended the Mid South Institute of Combat Shooting where I put this combo through the paces. I could not have been happier with the performance of both the light and the pistol. The only negative comment I have is this: I cannot find a holster for the G34 with the GLOCK light. They make them for the G34 with the other brand lights, but not the GLOCK light. This forces me to use a multi-fit nylon holster of lesser quality. I guess that's my problem though!