My quick ROI calculation:

1) Free power (currently available to my miners)
2) BTC increases at a more modest 5% per month
3) Difficulty continues on approximately the same pace we have seen in the past 3 months.
4) I can OC these boards to a modest 30GH/s (my luck getting a STABLE 35GH/s has been poor).

http://mining.thegenesisblock.com/a/867974c2e5

I make $4 after a year, BEST CASE scenario.

I'm bowing out this round, not worth it.