@raskul
Let us look into what we can do for the projection...
If you have your projection, would you please share with us? (Here is fine!)
We'd love to see how our customers see ROI Projections.
Its all speculation as none of us at Bitmain has a crystal ball
If you have one for sale and if it cooks me breakfast and make me some tea, too, let me know!!! love to have one

Here's my quick and dirty projection:
1155gh/s currently returns an expected .0147btc per day. Assume no diff change then 90 day return would be 1.323btc. At current rates that's $436 including psu. Thermalake is the cheapest PSU I currently see for $67. That would make the S5 cost should be $369 to break-even in 90 days with 'free' electricity. Any value to sell or mine with after that would be used to offset electricity costs and profit.
So basically if it can't gross it's cost in 90 days, I don't expect it to ever ROI. This is being rather liberal since diff will change and most have to pay something for electricity. I also don't take into account changes in btc price as if it changes, buy and hold makes more sense.