I have had a Venom, two RTS2's, two DPP's (first one died, and the second one has scratched glass), and one FTP Alpha 3. The ONLY site that I have not had any issues with is the FTP Alpha 3. It has served me well for over a year and I love it. Both RTS2's died (never again, cost me two matches), first DPP had battery issues, and my second DPP seems to work ok, but the lens has scratches that are not visible to the eye, but makes the dot totally distorted when set on high settings. I use a soft cloth to clean it so that is not the cause because I use the same cloth for all my sights and they are all fine. DPP is just a poor made red dot, obviously with poor glass.