The same can be said for any custom fit gun. A G.I. Rattle trap 1911 will fit most parts except barrel and be plenty reliable. I like the feel of the hand fitted 1911's. Hand fitting is not the mark of poorly made gun. Most high end 1911's won't take parts without hand fitting.
There is a big difference between custom and hand built
custom work enhances already nicely built components, wheras hand built is trying to get the parts to fit just to get the gun to function. Norinco are more consistenlt built than SAMs. Just because the slide and frame rattle a bit is not a sign of a bad pistol, accuracy may be affected though.
i have seen the most loose pistals shoot reliable, doesn't mean their are accurate. Also the tighest pistols shoot amazing groups, that have failures all the time. Its finding the middle ground that is the key.
you WILL find SAM pistols are NOT built to spec compared to the majority of brand name pistols. A lot of people try to get them to the same level of higher brand name pistols, but by that time you have spent the same if not more to get the same results. Spending more on the pistol than it costs is just crazy, unless you plan on starting from ground up like in Ed Brown, Wilson, Les Baer, and others
not meant to disrespect people that own SAMs or Norks, but I have had the experience of owning both, and have had the chance to see and know pistolsmiths from STI, bill Wilson, Ed Brown, Jim Clark, Dlask, Gunnar, and Mike Johnson from my 25 years of competition
I have see peole make decisions on shooting 50 rounds from a friends gun. The big thing is chose accordingly, but you can't really amke a judgment until you have put many many many rounds downrange.
... But you are the exception to the rule! My close friend had a SAM stainless steel commander in 9mm... What a piece of junk! Nothing but problems. Are you sure you have shot an STI? I've fired only two (one my ol Trojan)... But both of them where incredible. I am not an amazing shot... I'm okay for sure... But nothing special. I could consistently hit a beer bottle cap at 20 yards with the Trojan in 45acp. Couldn't hit it to save my life with my CZ shadow... Just for comparison. 
