bitmain is just effectively packing 18*4GB Gpus onto 3 compute boards and optimizing the bus so they work more effective(less power usage). with the p104 hasing @40Mhs, 18 of them would be 720Mhs but using over 2kW.
I wouldnt really call this an ASIC.
Regardless of power consumption, I think people are more worried about its easy purchasing and thus upping the universal hash rate and difficulty.
Its the first ETH ASIC so it's not going to be amazing. But it is the start of ASIC attack that is a worry.
Hoping for PoS soon.