Garbage. They started out as rebranded Shield RMS optics, and now they’re just a modification of the optic by the same manufacturer as per USO reps at 2019 SHOT Show. My agency (large metro agency) has tested several Shield optics and officers ran them both in training and on duty on Glocks and Sig P320 X models. No optic lasted longer than 4 months and had a 100% failure rate, so obviously they weren’t authorized for duty. They either lost zero, stopped working, physically broke somehow (they’re not impact safe), or the lens got scratched so bad that it was unusable. The RMS and first options by USO used an acrylic lens, which was terrible and scratched if you looked at it the wrong way. The new lenses are supposed to be coated with silicon dioxide quartz, which still doesn’t tell me what the lens is made out of (glass or acrylic) since according to my quick online Google-Fu you can put SiO2 on acrylic. Maybe someone knows more about this and can add something...but nonetheless, terrible optics. USO is using the same components and designs, so I believe we can logically have zero expectations of different end results.
For the money, get a Holosun. As much as I dislike that company, one can’t deny the solid track record of the 407/507/508 optics.