Is USB Erupter ever profitable?

[mintedstone]

The price of USB Erupter going down very quickly, and yet at 0.3-0.4 BTC each, shall we ever get the investment back? At the current diff, each USB Erupter can mine about 2.5X10^-4 BTC per day, which means it can get 0.4 BTC in 160 days (or 5+ months). But with BTC diff rapidly going up, I suspect that the investment can never be recovered. Is my computation correct?

[b!z]

Yes, buy it for cheap and mine while you find a buyer to sell it for higher.

[odolvlobo]

Whether or not it is profitable depends on how much you pay for one and what happens to the difficulty. In 6 months or so, the cost of power, cooling, and space will also become a factor.