The exchange rate of btc is always the wild card and if you say you know something is or isnt going to be profitable in this btc game youre fooling yourself. Looking back even CPU was probably profitable long after it was declared dead at today exchange rates.
https://bitcointalk.org/index.php?topic=1688.0That's right it took a few weeks to solve a block(50btc) with a CPU and the function was getting removed from the client because it was "pointless".
100s like this
https://bitcointalk.org/index.php?topic=3994.0 +10
I was fortunate to buy usb be's at $7 so I have made my roi, but now that I'm in the "profit" side the difficulty has made that a very slow process.