I picked one up a few years ago. Admittedly, it was a throw-back to my days spent playing video games; I always had a soft-spot for auto-shotguns in them.
Anyway, its an interesting gun, though overly long due to the nature of the receiver, IMO. I've been meaning to do a pistol-grip and folding stock conversion on it for about 3 or 4 years now, but still keep putting it off. I just can't justify putting more money into the gun that I don't really use. Even as a sporter, it gets lots of attention and always brings out some comments from those who see or hear about it.
Over,I like it, but it just sits in the safe. I probably wouldn't buy one now, unless I came across one that was already converted or was at a heck of a deal.
I think Technosavant summed it up pretty well. I'll add a few things, though.
Mags do seem to be more readily available these days, but I still have but the 1 4 rounder it came with. I think 12 is as large as I've seen, usually for ~75$ range at local gun shows. I have heard mags need to be custom fitted with a little filing to fit your receiver. As I have never bothered to buy one, I can't speak on the matter.
I've also heard of instances of rim-lock using the shells in the stacked magazine. I've never had any hang with mine, though.