i have 5 aimpoints and have been useing some for 20 or so years and not one has failed me ! with a many thousands of rounds fired with each scope, i also have about 20 other red dot sights IE tasco, redfield , i have tried , leupold, millet, burris, tru glow, bsa, docter sight, ultra dot .and the aimpoints are the best in my opinion with the redfield esd in second place considering crispness of dot , field of view, clarity & brightness , and 100% paralex free not like some makes that make that clame but are not!