The cost is based on the current ETH price, if it goes up by Jul, the next batches will be more expensive.
The real cost is 800 + 200 shipping (in US) + 130 ATX power supply, roughly 1100$ at the current prices, close to zero resell value.
The same efficiency as GPUs.
Takes less space. Huge +++
A lot of noise, around 80dbl ?
So it will drive GPU prices down until they reach the equilibrium.

This won't kill GPU mining, but the GPU prices should get back to MSRP, that is a good thing.