Well, for all I've seen, the main problem, that affects almost every piece, looks to be the black lines in the silver parts... and the silver painting itself. The yellow and red parts are good, not excellent, but still acceptable. They are brighter than the prototype, but that doesn't make it worse.
Buuuut, every international customer must realize this: Iron Studios probably won't have a return policy to deliver a new statue free of flaws. And even if they develop such policy, the replacement will still be here in Brazil, which means that more costs will be involved (shipping, taxes etc).
Therefore, my advice is: take your time to calmly check every single picture available, and then make your choice knowing that once it arrives to you, it's probably definitive.
My personal opinion? It's still a good statue, afterall most of us will put in on display and look from a distance. Iron Man fans should take it. But if the closer details bother you, keep your distance. At this price range, we expect something near perfection. Unfortunately, even Sideshow isn't delivering what we want lately - we can't expect a rookie brazilian company to do so.
Hope that helps those in doubt.