I have. I used to own one. I got a good deal on the AB ring flash and the used kit I bought came with the moon unit. I thought it was the dumbest name for anything in the world. I put the thing together, looked at it, and said, “That’s sort of stupid.”
Then I shot with it. Now I’m a believer! It’s a great light. Great enough to use all the time? No. It’s a one trick pony when you use it as designed. I have used it off axis before as a small softbox but I already have a small softbox that does that job. I ended up only using it once or twice a year… even though I liked it. I just don’t go for that “look” very often. It doesn’t fit with a lot of my work… so I sold it and let that finance something I’d use a lot more. I think that sale went to buy some C-Stands.