[Hectic]

I wouldnt say its entirely based on opinion. It is prety much a fact that VFC has some of (if not the) nicest externals, especially when it come to AR's and IMO the hands down nicest 416's and 417's on the market.
internally they have improved by leaps and bounds and the only fault I found in my 417 was an aluminium piston head and a polycarb piston. Head should have been some kind of plastic and piston should have been some kind of fiber reinforced polymer.
For sure of the brands suggested they are going to be the nicest externally and just as good internally.
if it was purely opinion i would say just buy a JG or Echo1 and drop either a pre built or self built lonex box (most of my guns are china crap with good parts put in and they all shoot just as well or beter than my stock vfc417 did and the cost was about the same, 250 for the gun and 150-250 in parts.) I know the OP was askin for our opinions but perhaps i should ask this. What do you want out of the gun. Do you want the best looking gun, best performing, or a workhorse, looks okay shoots consistantly and can take a beating without you caring about a scratch or scuff?