Bitmain S7 has a hashrate of ~4.86TH/S and consumes 1210watts, significantly less per GH than Avalon. The main problem is just the costs and the availability.
While bitmain s7 is around $1,975.00-$2,659.00 consumes 1210 watts. Ebay price
Avalon has a hashrate 1.3th/s and bitman has hashrate of 4.66th/s
So if i will buy 4 avalon total cost of $1,360 Hashrate is 5.2th/s then total watts is 2760
the difference is the price and the wattages.
I realize that bitmain is good than avalon hmmm... but in the long term.