If they do deliver you will have the best miner on the market.

6 TH at 13% increase every 2016 blocks from 1 August will ROI in about 80 days not factoring electricity. 

Free shipping is great.

Still on the fence though.

At currents rates this is 10+ BTC.

Also this miner will only make ~5.5 BTC profit for the rest of the year(not factoring electricity).

So basically you have to risk all this, take care of the miner and if all goes well you will make ~$2500 - 5 months of 2.5 KW electricity by the end of the year.

But maybe the diff increase could go below 10% for the last months of the year.