Tempting... but still not a good deal. Sorry Bitmain.

Take a look at my spreadsheet, play with the editable cells and see for yourself.

Unless the S1's are recyclable in 2015?...

https://docs.google.com/spreadsheets/d/1giwtVGpz19QOZvGuCWsHgyPfpOM4Zh8-Rgk0jvAHdGM/edit?usp=sharing

Average past difficulty jumps: 23% every 12 days.
Difficulty estimation: jumps 15% every 12 days.  But you can change that also in second sheet.

Comments are welcome. I'm always looking to improve everything. 

- Kex.