I've never had to use the forward assist on any of the AR's I've owned over the last decade or so.

But I have a good story about the use of one.

Good friend of mine shoots a lot of 3-Gun. Has a real nice JP-15 that he used in competition.

One day in the heat and pressure of competition a round wouldn't seat properly so he wacked the forward assist, put sights on target, pulled the trigger and BANG! ... blew apart the $$$ rifle he spent many moons saving for. Seems there was a squib load stuck just inside the barrel, protruding slightly into the chamber. Slamming the FA caused the bullet to set back in the case which spiked pressures even more making the KB! worse.

So I guess the lesson is, if you ever actually NEED a forward assist, you should probably be breaking down the rifle and looking for obstructions instead.

Point of all this rambling is, if you find a good deal on an AR sans Forward Assist, buy it (especially if it has a dancing pony on it).