It infuriated me no end when I would have someone dead to rights with an AR or SMG only to be shot at long range by a shotgunner. Then I would realize it was the KSG and it would aggravate me even more. Finally, the other day, I decided I would adapt the "if you can't beat them, join them" mentality and started a KSG class. My goodness, this gun is fantastic. I was pleasantly surprised with the ease in which this gun kills. No BS hitmarkers, if you do get a hitmarker, then the opponent is out of range and you will more than likely die because of impatience. If the gun hits within its range, then the other guy is dead. I do realize that this is one those guns that doesn't give much room for error because there have been a few times I've missed only to get cut down. But man, more often than not, I love outranging guys running with scorpions, pdws, or msmcs. Gives me a chuckle every time.
The KSG is an incredibly awesome shotgun. There's nothing quite like the rage you get from sniping someone from halfway across the map with a shotgun. However, the problem is it's inconsistent and too dependent on your connection. I have games where I go 40-2 with it, and other games when I struggle to remain positive. The hit detection can be absolutely atrocious at times, and I've had games where the KSG refuses to land a hit, despite clearly being on target.
In most cases the R870 is simply better. In games where you do especially well with the KSG, you would also likely do just as well (if not better) with the R870. It doesn't quite have as much effective range, but it simply outperforms the KSG a good majority of the time in it's respective range.
KSG with a silencer is awesome for flanking though, you can wipe out a whole team before they knew what hit them. Also, in the likely event you miss a shot or two, you won't show up on radar.
KSG: Silencer-Stock-QD ;)
We trained harder than you today, and we're gonna party harder than you tonight. Mint with the crew.