this is the Mark 3, it only came out 5 months ago, so don't compare this to other deals because it's not the same product. i don't even know why i'm saying this because someone is going to do it anyway....
it's grey market. if you don't know what that means, google it. seller has 60K reviews with 99.6% positive feedback, their deals on TVs and cameras have been on the front page a zillion times. i bought a sony A7r II and various lenses from them, haven't had any problems.
that price alone is not that great of a deal unless you also get ebay bucks too. there is an ebay bucks promo going on right now for random accounts. ebay bucks activation: https://reward.ebay.com/rwdwebui/...ram3=Bucks
if your account is eligible, you will get $100 back in ebay bucks. i have 8 ebay accounts, 2 are eligible. you can create as many ebay accounts as you want and pay with the same paypal account on all of them to increase the chance of getting these promos.