I have one on order, has been for about a month now. I've seen reviews of varying opinions.. everyone agrees the capacity and the looks are awesome. Some think the build quality and the actual usefulness of the gun (ie, switching ammo feeders, etc) leave some room for improvement.
I havent made my order for mine yet, but I know I'm def getting it. Switching feeders seems like a little hassle, and I've heard of some of the forward pistol grips breaking off, but I've also seen some of the solutions for the handle problem (different pistol grip with more bite on the rail).
If you have one in your hand right now, I would tell you KEEP IT. They are great shotguns. If you haven't got one yet, you would be better served spending your $$$ on a used shotgun for $175 to $275 and the balance in ammo. There is also a company that makes a semi-auto gun like the KelTec with a multi stack drum mag. It holds something rediculous like 24 rounds but it costs as much as three KelTecs and as much as 10 Remington 870's.
On Sons of Guns, there is an episode where Bellini asked them to make a competition shotgun and they used (on one gun) a drum style magizine like GTGallop has made mention off. I can't remember the name of it but it was in this current season of the show.
I saw this gun, KSG and decided I could buy allot of shotguns for multiple purposes for the price of one KSG. Don't get me wrong, its one killer of a Shotgun and one to have in a collection for sure.