I have a Crimson Trace on my Government Model .45 acp.
I see the laser’s use on handguns as (not in order):
1. Target identification (This one, marked by my laser, is mine).
2. Shot placement in unusual situations – anytime I can’t, because of awkward position or injury, line up my sights.
3. Small degree of psychological impact (See that pretty red dot on your chest? Guess what’s coming next). I can’t count on this though, and they have to notice the dot – but seeing the pistol pointed at them should be enough of a clue.
4. Training. It’s really easy to detect trigger press errors by watching the dot.
I don’t use the laser to replace my sights (except in “2” above), and I don’t trust batteries, switches, or possible frailty of the laser. I also don’t use one as a “night sight”. I learned to shoot well in low light with just my standard sights. Being able to identify the threat is more important, and a laser won’t help with that.
As for putting one on my shotgun, it’s not likely I would. Because of the “spread” of shotgun pellets, shotguns are a point and shoot system at typical ranges, so the only advantage I see is possibly in “3” above – not much of an advantage for the cost.
But, hey, if you like it, get it. The big name brands are pretty stout now, so I don’t see recoil being a big issue.
I also have a problem with attaching flashlights to my long arms. They’re muzzle end heavy to begin with, so I don’t need to add additional weight out front. Try doing a full reload, shotgun still mounted at the shoulder, holding the shotgun only at the wrist of the stock and loading shells with the other hand, while keeping the shotgun pointed at the "threat". This gets tiring without the additional weight forward that the flashlight will add. I’ve gotten to where I prefer really light barrels on my “practical” long arms to reduce the forward weight.
Now, if I was leading SWAT team into a darkened bad guy building, then I would appreciate the flashlight on the shotgun. I have yet to do this though and I don’t foresee a need for me to do this anytime in the future.
But, hey, if you like it, get it.
That FN does look cool, and FN makes a fine gun. It would be too big for my hand though, so I could never be as good with it as I am with a gun that fits properly (and I really do not like the so called traditional DA/SA triggers).
I had a tough time getting many soldiers to shoot well with the Beretta M9 when I was giving M1911A1 to M9 transition training to both the 8th ID and 1st AD. The M9 is just too big for many hands and the DA/SA transition trigger is both too long and difficult to master (not impossible, just difficult).
But, hey, if you like it, get it.
At your service,
Friday nights (FSO) at 11 PM Eastern 
