I shot one donkey's years ago (1999) when Francotte (before they went bust and closed) considered reintroducing them under the Francotte name.
My impression: Light, very responsive, handled very much like a SxS British game gun, and that's how you had to shoot one - swing through and shoot. If you shot it deliberately, like a typical production 12-ga O/U, it died on you in swing and you (I, at least) would miss behind. A better shot may not have had this problem.
I found the ergonomics odd, but then I didn't have one in hand long enough to get used to it. As I recall when I'd press the sidelever down, I would want to open the barrels down.
They appear often enough for sale, in enough places (USA, Europe, UK) that I wonder if the widely quoted production figure of about 250 completed guns is not low, but that is only speculation.
Personally I think they are kinda cool.
