I've only ever used 2 light guns in my gaming life: The bright orange one which came with the original NES to play Duck Hunt, and this, the Desert Eagle replica by Thrustmaster.
Apologies to anyone that doesn't know firearms terminology, this review might confuse you slightly...
My first impressions of this were quite good, it looks realistic (if you disregard the wire coming out the bottom of the grip, which connects to your PS2, PSOne or original PSX). However, after picking it up, any resemblence to the iconic weapon flies out of the window. Considering it's supposed to make your games feel more realistic, they really should have made the gun more substantial, it's far too light. I also don't like the way you can set it to auto-reload if you want to. Normal reloading is also unrealistic, you push a button on the side just under what represents the top slide. They should have just put a button plate on the bottom of the grip, so you can slap it with the palm of your hand as if you're sliding a new magazine into the weapon. Another problem I found is that the trigger spring is far too light. There are some nice touches though, such as the "laser" sight under the barrel having a d-pad on it which is quite accurate to where the calibration dials on actual laser sights are.
I used this on Resident Evil: Code Veronica on the PS2, and aside from the previous flaws, it handles well. The accuracy seems, well, accurate, and there are no delays caused by the long lead connecting it to the console.
I think I might have liked this lightgun more if I didn't have experience with actual firearms in various guises. As it is, I can't look past the "realism" flaws, especially the weight and reloading.