Two important things:

1) In China there is currently a crackdown going on against anything BTC. It may mean that the december batch (from Bitmain, located in China) will never arrive.

2) What has not been addressed so far: Gigawatt does not turn off your miner even when mining profits are lower than MEF (electricity/hosting). Gigawatt does not turn off or destroy your miner, it offers only to ship it to you once it's not profitable anymore. You pay for the costs of shipping/customs which will be a lot if you order several miners.