I'm an old space nerd, so when I saw one of these it was a moral imperative to get one eventually. Well, the timing was finally right -- I got this yesterday, and from a seller in the states so I wasn't paying as much for shipping as I was for the item.
It's more than a little reminiscent of the Parker 51 at the business end -- hooded nib, small opening and all -- and the piston mechanism works just fine. It's very light, just 10g, but it doesn't feel flimsy.
However the nib does have some damage, so I'll have to figure out how to get it out of there and replace it. Anyone with experience with these, I'm all ears.