Yes I have had it apart, all except the mechbox, as it's going on at least the third season with no problems.
http://www.airsoftcanada.com/showthread.php?t=93112
there is the review thread.
"...While Ill admit I have not handled the G&G Sig 550 in person...
Well maybe you don't have any basis for comment then do you.
a review of the G&G SIG the ICS SIG and the KA 556
YouTube- AATV Video Review: SIG Triple Threat Match
* the negative about the pistol grip being small... well, it is exactly the same as the real steel ... the TM and JG pistol grips are larger than the real steel. Also the bipod functions exactly the same as on the real steel. The real steel doesn't lock either.*
there is also a review of the G&G vs ICS vs JG done by AATV which I can't find yet.
maybe some people like looking for/ or buying a new bolt handle?? or having stock wobbles... I prefer a reliable, solid built gun, of which the G&G SIG 550 is, and which the 552 should also be, as it is the same platform with only the shorter fore end.
I don't think I need to defend myself further....