Bitmain has been trusted as a miner company, it is safe to buy from them as you are guaranteed to receive your rig right at your doorstep.
However, recently they have been known to ship their orders late, so expect your rig will arrive later than expected, especially in Christmas Season as shipping company will be busy and may not be able to ship your items into your country until January.
I have understand about the bitmain site bro but they are delaying the production and delivery long time this made people go towards the dealers who is selling it for high price.
Still some people says that delivery is faster and it is reach with 20 days after ordering the international shipping.
I think even that delay also happening due to bulk order made by the resellers only.