I'm not a fan of G&G guns. The metal is the opposite of Marui plastic - Marui plastic looks like metal, G&G metal looks like plastic - at least on the ones I've worked on. I've also found them to be lacking in that the air nozzles did not have o-rings and the cylinder heads did not have any form of bumpers at all. It was just metal hitting metal, which to me is a big no no. Small issues that I'm not sure why G&G hasn't fixed yet, but until that's done I'm not buying one. I'm not saying G&G is bad, I'd just prefer VFC. I've also seen a G&G with "G&G ARMAMFNT" engraved on it. Yes, "armamfnt".
Maybe the Top Tech guns are different?
Guardians of Asgaard - KF32
VFC H&K 416C
VFC KAC SR16 JL Billet SBR
TM FN Five-seveN