When I get a chance to use it, I'll try to drop back in with some thoughts.
However, I can say that a friend has one, and I've seen it in action through my Gen2+ D121M (he uses a Gen3 Litton). Was very visible, and I was able to track it easily, but until I get it on my rig, I can't really offer too much else.
The zero adjust is a bit goofy compared to what I'm used to with regular reddots/scopes,etc., but he said it wasn't too bad to get zeroed in. It's more solid than I expected as well, and looks to be of good construction, etc.