About this hashra miner correct me if i am wrong!
So it can output 6.6MH/s with 120-140W for $4,695.00 + 220$ for shipping

This equals to about 9 r9 280x assuming you get out of them 740kH/s
now you will need also
2x motherboards
2x ram
9x pci-e risers
probably 2x CPU
now depends on PSU you will need 3-5 of them
so this would cost me around 3300 ish € which is around near 4500$
now also consumption of such config would be around 2500-2700W

And for Euro zone i was kinda generous with figures in prices, considering the amount of heat and noise conventional mining rig produces + space it consumes this Asics looks quite compelling.
Dont forget this is just the first generation of scrypt asic.

There is of course  a big + a conventional rig has. That you can resell it.