BTC price is irrelevant to ROI IMO. You basically pay ~0.75 BTC, and this machine will produce 0.75 in a few months.
Really? BTC price is crucial to my decision to purchase a miner or not. If you can't profit in BTC it doesn't mean you can't profit in fiat. If I know with almost absolute certainty that I can profit in either btc or fiat, ill buy a miner; if I can't profit in terms of either, I pass.
In terms of BTC, my block erupters were disastrous purchases. But, I ended up with a ~700% fiat profit. All I had to do was immediately repurchase the BTC used to purchase the erupters.