SIG or M16? Well, I use the SIG 90% of the time.
As light sniper gun it's more useful than the M16, since the LAM works fine at closer quarters.
As AR I take it because I can work better with the sights(I even achieved some long distance kills at ExtremePrejudice with the iron sights alone!) - funny thing is, I never use it on full auto; why should I, a 3rd burst mows down anyone, and a second burst can follow quickly. The only drawback is the mag capacity(which I suggest to change to a 30rd mag, which is available for the gun)
The M16 I only use when I feel the urge to use the M203 - though I get more often killed using it because that damn 40mm doesn't explode.
The 3rd burst of the M16 is the best feature it has - I can fire succesive bursts at nearly full-auto speed but still remain better on target.
In fact I only prefer the SIG because I like it more..
Snakeye
anything you do can get you killed, including doing nothin