OK, first let me say that I am not a fan of the Norinco AR's. I know a TON of people will soon pile on and tell me how wonderful their Norincos are, and that's great for them, but please hold fire for a moment until I finish.
What I dislike about Norinco AR's has nothing to do with their being Chinese, nor their sometimes questionable visual appearance. None of that matters if the rifle is reliable and shoot to point of aim. What I have issue with is their seeming lower than "industry standard" QA/QC record. When you get a good Norinco, it is certainly good enough as a "go to" rifle. The guys who get these rifles are the ones who always flag wave about them. But for every 4 or 5 guys who are happy with their rifle, I see one who has issues.
By issues, I mean poor fit of upper to lower with a big gap and lots of wiggle, or casting flaws on the bolt stop, or in one case a gas key that was not through-drilled (i.e. single shot AR). The list goes on.
Now that being said, if your Norinco has proven itself functional and reliable, there is NO REASON to buy another rifle. Unless you want to take it to the states, and I assume you don't. Ar's are modular and the Norinco is fairly good for taking most aftermarket parts.
What I do recommend is that Norinco owners buy a cheap DPMS front handguard cap and replace the stock Norinco one. This solves the Norinco drop-in handguard compatibility issue. You MIGHT need a gunsmith for this depending if you have th eright tools to properly remove the front sight block or not.
I don't recommend dremelling your magpul furniture to account for a dimensional issue on a $2 part. Just replace the $2 part and be donw with it. Then enjoy your rifle for what is it and stop worrying about what it is not.
If you want to use a free float HG, you need to remove the out of spec cap anyhow as well as the front sight block. This is not specific to the Norinco, any standard AR is identical, so buying American won't put you any further ahead.
People who can't sleet at nigth because their proven-relaible AR doesn't sport a pony or a Noveske cross are less about shooting than they are about mall-ninja'ing anyhow.