i had them build two uppers.
the first one... they forgot my order, but gave me some free stuff in return.
the 2nd was a FTF they built it for me while i was running around, they had to try twice since they put the wrong flash hider back on. but fixed.
i later went home to find that the retaining pin on my troy rail was crap. the rail uses a pin, someone had lost it or somthing, because what was in mine was a small aluminum ball bearing.
i called them and troy, they said i could send it in but i figured that would take too long sinc ei could fix it myself.
i tried to get the replacement part from troy, but they misunderstood me and sent me a rail clamp for a BUIS... the wrong part.
being all i needed was a small pin spring loaded to fit through two holes i machined one out of a brass rod.
so they do screw up. and help to fix but i dont think they try real hard
-p.s i was dealing directly with J&T they are located about 45min from me.