The gun basically acts like a mouse and there is no, to very little lag (not noticeable to me anyway). Of course, if you move the gun very fast and with big movements, the led bar maybe can't process the movements as fast as you move with the gun. For the most shooting games you have to aime acurate, so you will not make big and fast movements anyway. To go short: I played for about 15 minutes and had no problems with lag. A factor for lagging is also - I presume, the hardware setup (CPU, GPU, memory). I have a 1.8 Dualcore and a 4 year old mid-range GPU. The accuracy of the gun is good, no problem there. You have to calibrate the gun only once. Installing the gun and led bar is just plug & play actually. I had some problems with MAME though, but that had nothing to do with the gun. Once I removed AdvanceMAME, the gun worked great in MAME. Maybe I had not configured AdvanceMAME properly, I really don't know. I'll figure that out later. The gun has really a great fun factor for me. I'm even considering buying a second gun. But to my opinion, the Arcade Lightgun from Ultimarc is a bit too expensive. The gun is entirely made of plastic. It's solid and strong, not like some 10 dollar water gun from your local toystore. But beyond this, no fancy stuff. The fabrication of the gun, the led bar and the electronics is so much cheaper than the selling price (100,- euro's). But to me, the fun factor beats the price.