I got mine to shoot CQB. I tried a SKS and a 858 but I could see that mag changes were much smoother withthe AR platform.
Mods to date:
Floated the barrel. Kit from Brownells was only $39 and it installed easily.
Rock River match trigger. About $100. What a joy!! Best mod I made.
Hogue rubber pistol grip. Feels much better.
Instead of a riser I used high see-through rings. $9.00
Tasco 4X scope (Post reticle) $17 on ebay.
Muzzle brake. Gift from my son. It is supposed to reduce muzzle jump. I suspect it works because I now shoot rapid matches as a series of double taps.
Doubled mags. Glued together on a piece of wood and wrapped with tape. Worth a few seconds on a mag change.
I have about 1000 rouns through it now. In the beginning I was not cleaning the bolt inside the carrier and it started to jam. Better cleaning has made it 100% reliable.
Accuracy is not as good as my other AR-15 rifles (Colt and Olympic). Floating the barrel made no difference. But it was bought for CQB and I am getting good results with it. I am getting a kick out of being competititve with a rifle/sight set up that costs less than half of most of the other rigs on the line.