Look at the overall rate of 159THs @ $3.5 per TH = $556 per day = $16,695.00 per month Gross Profitability
$16,695.00 Gross
-$ 1,500.00 Hosting Fees
$15,195 Net Profit per month
$50,000 Purchase Price / $15,195 = 3.29 month ROI
Solid Machines with a Great Profitability.
I get the math, but it relies on the assumption that all the machines will last over 3 months. Given some of their current hash rates it doesn't look like that's likely (unless they are being underclocked). So it seems like a far better investment to hold btc unless you are willing to negotiate on the price.