dont forget that in 2016 btc income from mining will be half
but the value will be also very high, the current value already is about 100% more than what it was, so easily at this point will not count anything, incomparison when we were at 230
The price of bitcoin is not certain to rise. That is just a speculation. But the blockreward is going to halve, that is certain.
For this it is a big risk to start mining now.
Sure you can profit easily for 6 months.
But.. then what?
The bitcoin price might rise in long term. That is caused by adoption of the bitcoin as a payment method. It is valuable investment as well.
I think if you believe in bitcoin you believe it will rise long term. Mining is no guaranteed profit, you have to enjoy it to do it. Also you are speculating you will make a ROI.
This thread thought can pretty much be done long and short term. 21 cent's is just to much to mine on. As long as you can get a data center for half of that, it's a far better option.