I think the initial QC would be the same, what the vendor is selling is hard to say, is it straight from the factory? Is it an open box item? Floor sample? I am a cautious person and something like this with a $600 differential would concern me, usually the difference is not that great, which is why I stay away from grey market items. I guess it comes down to the vendor reliability and reputation. There might be nothing wrong with it and may be a bargain, or it may not, a gamble and you can decide if you want to do it.
Alan