I still can't figure out why someone would pay $800+ for an S7 on eBay when you can get a brand new one from Bitmain for less. When I ordered mine, it took less than a week to arrive here in the U.S. No problems with customs, etc. Very smooth and easy. You could probably do pretty well buying a bunch from Bitmain and turning them around on eBay.
I guess there have been so many problems with new S7s that folks prefer buying used units that have already been field tested. Then they know they will get one that works right out of the box. I have been lucky, I have 4 batch 1s, a batch 10, and 2 batch 11s that all turned out to be rock stars in my book...on specs and not a bit of problems.