I was in this boat while trying to make a setup lighter than the current LPVO + offset red dot it currently carries. My friend has a 512 but I do not know anyone that has an AEMS. The 512 is pretty nice and slightly cheaper than the AEMS right now, but it weight almost double, comes at absolute cowitness, does not have the ability to take other mounts, and is pretty chunky. The AEMS is very light for a full window red dot, comes at 1/3 cowitness which is what I want, and is supposed to have a very large window relative to the body size.