I put a set of Wren Tech's Advantage Tactical Sights on my Glock 34 this summer. I really like the combination of a fast sight picture up close and pinpoint accuracy at longer range. I have been using these sights for a few IDPA, USPSA & Steel Challenge matches over the past few months without any issues, other than holster fit. The wide, large front sight post will not fit any of Comp-Tac's holsters. Since Comp-Tac is arguably the most popular IDPA and USPSA Production Division holster, this is an issue. G-Code, Blade-Tech & Ready Tactical all fit fine, however, so there are options available. I recently completed OpSpec Training's 3-day Advanced Pistol Operator Course-C (APOC) at Central Florida Rifle & Pistol Club in Orlando. I fired at least 2,500 rounds through the G34 during the three-day course, so this was the first intense workout for the ATS sight set. No issues with sights on day 1 & 2, or the first 1,700 rounds. On the afternoon of day 3 around the 2,500 round mark I suddenly could not shoot a tight group at 25 yards. Unload & check front sight; loose. Very loose. Back when I installed the front sight, I followed the directions exactly; once zeroed to the 147g ammo, the screw was installed with Loctite 242 and snugged down with a wrench. Due to the Loctite on the screw, it was impossible to remove at the range, so the gun was effectively done for the day. Since I had a backup pistol, not a problem. Completed disassembly at home and was surprised to find that 2 of the little plastic elevation shims had been completely destroyed. I never use solvents on anything but the bore, and that is always done away from the rest of the gun; so the front sight has not been exposed to solvents. Class was done using G-Code holster with ample sight track, so there was no physical impact to the front sight. The only causes of the shim failure I can think of are heat and repetitive stress. Day 2 of APOC averages about 200 rounds per hour, and the gun does get pretty warm, although manageable without gloves... probably hot near the muzzle, although I never checked. Certainly some blast residue from muzzle surrounding the front sight. Perhaps the sight screw started loosening, which allowed the shims to slide back & forth between the sight & base, causing the thinner shims to self-destruct. You can see what's left of the shim in the photos. The ATS are still my favorite sights, but I certainly wouldn't put them on a service or carry pistol, they're too fragile. This same G34 went through a 3-day OpSpec Practical Fundamentals Course last year with no issues whatsoever while wearing Warren Tactical Sights, which are very durable; even if the fiber optic rod falls out the front, you still have a useable front sight. I'm not sure why Wren Tech goes to all the trouble of offering 5 colors of front sights and 5 different rear inserts, when almost everyone seems to use a yellow rear and red front. If they could figure out the proper front sight height for each platform and make a one-piece front sight, these would be much sturdier sights. Eliminating the base/sight/shim system would allow for a smaller footprint on the slide, and possibly fit the popular Comp-Tac holsters as a bonus. Bottom line: Great sight picture but fragile product as installed on Glock. Holster fit an issue for Comp-Tac and any other narrow-track holster. Replacing the delicate (breakable) multi-part base/shim/sight system with a one-piece front sight would drastically improve the ATS system.