I have the "Black Shadow" Winchester SXP that came with the 28" barrel as well as the 18" Home Defense barrel. I absolutely love mine. I've ran about 10,000 shells through the gun since I've had it. I've had absolutely no problems with it whatsoever. The things I love about the Super X Pump are as follows:
-"Speed bolt" system. Everytime you fire, the bolt flies back almost all the way so all you, the shooter, have to do is pull the pump back like an inch to eject the shell, the slide the pump forward to chamber the next round. Winchester calls the SXP the, "Pump action that thinks it's an auto-loader" once you shoot the SXP, you understand why. Very fast pump action shotgun. In my experience, if you shoot 00 buckshot through it, or 3" game loads, (basically, a shell that has more power than a target load) the bolt will fly ALL the way back and eject the spent hull, so all you have to do is slide the pump forward to chamber the next shell.
-It's back bore'd. .742" You can run pretty much any kind of ammo through the SXP and she'll eat it, which is a huge plus when you demand reliability.
-Chrome lined chamber, and barrel. You can run steel shot, tungsten shot, pretty much any kind of shot through this gun and it won't hurt the barrel (If you run a lot steel shot through an ordinary gun, it will eventually damage the barrel. NOT the case with the SXP because the barrel/chamber are chrome lined.)
- And lastly, 5+1 capacity. Too many companies anymore make their shotguns only capable of holding 4+1...I don't like that. The more ammo in the gun, the better.
Now, I can't say much about the SXP variant with the 3.5" chamber because mine only chamber's 3" shells, but I'd bet you anything you'd never have a problem with it...EVER. Winchester is the best kept secret as far as shotguns go because everyone thinks they have to have a Remington 870 (junk) or a Mossberg something or other. Winchester's are the sh*t and always will be. Get the SXP, you won't be disappointed.
-Light weight and COMFORTABLE! Is light weight in that, the stock and pump are made of polymer plastic (VERY TOUGH plastic, not cheap at all!) and the gun has an "Inflex" rubber butt pad. The Inflex rubber butt pad is fairly thick, it shoulders comfortably, and you could shoot all day and have no pain in your shoulder. The gun feels like you're shooting a 20 gauge...not even exaggerating at all.
BTW: Look around on http://www.gunbroker.com
for a good deal on one. The one I have (Black shadow, 3" chamber, 28" barrel, and came with the 18"HD barrel) retails at around $480. I got mine on GunBroker for only $270 BRAND NEW. It pays to shop around.
Hope this helps!!