At the point where they pay the average mining bond equivalent of dividends at ASICminer's tube cost-per-GH/s price.   That price happens to be around the current B.MINE price - https://bitcointalk.org/index.php?topic=99497.msg8329684#msg8329684, so my price floor on PETA is therefore going to be in the 60-87k satoshi range, assuming the difficulty levels out again after this bump and based on future difficulty movements this period and onward.

Here's a spreadsheet that linearizes the past 3 difficulty intervals (since they were relatively small) for PETA's output against the new ASICMINER tube and also against B.MINE: https://docs.google.com/spreadsheets/d/1ZoapItfWpxHxWObZ0RxTHrU8Ae8ox28GmfUr2wD-QMA/edit?usp=sharing

Note the analysis factors in electrical costs for the AM tube running at 900 W for BTC at $515 with electricity costing $0.12 per kW-hr.  The linear regression model depreciates the dividends more aggressively (56-60k satoshi range), while the difficulty bump (estimated for next period at 17.7% as of now by bitcoinwisdom) shows for more realistic average payouts based on known difficulty forecasts (my high forecast for 87k satoshi).  You could use bitcoincharts' estimate of 9.765% for a more risky price forecast (i.e. possibly overpriced) if you're still bullish on PETA.  Keep in mind that the yields assume the current BTC-USD price and electrical cost ceteris paribus across the model.

TL;DR if you're not pricing against the newest technology, you'll consistently see your assets are performing poorly, and you'll often end up losing on the price depreciation as competing capital seeks substitutes.

DC - I own no shares of PETA and have no plans to enter into the market within the next 2 difficulty cycles outside of the price range I have specified above.