Got the SP20s today. NICE units.
I'm going to give them a few hours to burn in before I start looking at the numbers.
I see why people say that 1.7TH isn't realistic. Mine are steady at 1.55 after an hour with the standard settings. I'll play with those a little later in the day when I have time.
I'll say this though, the QUALITY of the boxes is superior in every way.
This is also where your cost minimization come in. Everything I have read indicates that the last 200GH area really pretty expensive to obtain in terms of power cost. There are multiple SP20 threads, even one that includes efficiency plotted again hashrate. The higher the speed, the higher the $$$/GH.