I'd rather have an M1 or M2 Benelli or even one of the new Beretta shotguns.
The KSG is a neat idea, and I'm glad to see someone taking a bit of a risk on a new design. The problem is that someone is Kel-Tec, home of the awesome idea, mediocre execution, and limited production.
While the KSG is a neat concept, it's suffered from all kinds of developmental problems, and no one seems to have been able to get through a 3 gun match or serious shotgun training course with one.
The other problem is that it's a manually-operated shotgun in a world where there are at least four extremely well-made pump-action shotguns that have been available for the better part of a century. On top of that, we now live in an era where reliable semi-automatic shotguns are now extremely common-place, and often times at a price point at around what a KSG goes for. For my money, I'd rather have a semi-auto shotgun with a 9-round capacity than a pump-action with a 15 round capacity.
Which brings me to my biggest gripe about the KSG. It's a pain to load, reload, and do select slug drills with it.
Granted, reloading a Benelli is no picnic, either, but with practice it's possible for even an average shooter to fire a round, load eight shells in it, and fire another round in about eight seconds.
From what I've seen of the KSG, there's no way to quickly reload the gun, as the design requires you to reach up and inside the gun. This would make reloading difficult, especially when moving, as you're going to have your hand jammed into the action of the gun practically up to your wrist.
Ok, yeah, I can hear you objecting "My KSG has a capacity of 15 rounds! I won't need to reload!"
Let's assume you're right, and there's a magical capacity that renders the need to reload moot.
Great. Now what are you going to do when you need to load an individual slug to hit a target at range? You're still stuck with having to work around the KSG's terrible loading interface, and even the best techniques for loading the gun require you to tip the barrel toward the ground and stare into the loading port, which is going to be a problem if you have to move, or want to keep an eye on your target.
From where I sit, the KSG is a one-trick pony with a slogan of "Capacity Uber Alles!" The problem is that this fixation on capacity negates the one thing that shotguns do really well, which is the ability to specifically tailor ammunition to a given task.
Now, if they could take the capacity of the KSG and graft it onto a semi-automatic design that allows for easy reloads and select-slug drills, then you'd have my attention.
As it is, I can already get two of those things (capacity, fast reloads) with an MKA1919, which also has the added advantage of being semi-auto.