AGM benefits are onboard recording and wifi, and Bering Optics benefits are proven performer, better warranty, and serviceable. The AGM Rattlers and Taipans are 100% made in China and imported in. AGM totally admits this. If you have an issue with a Rattler and it is under warranty, most likely they will replace because they don't service them. The issue is what happens when your warranty has expired. I asked this question directly to an AGM rep and he would not respond to that question. The answer appears to be you have an expensive paper-weight.
I have never used a Rattler but from people I have talked to who have tested both side by side seem to say they are fairly close in image, with the Hogster having a little better quality image. I have used a Hogster 35, Phenom, and Super Hogster down to -25F and they worked flawlessly.