Just to add my own thoughts regarding this matter.
I do not take into account the fact that most of the upcoming mining plattforms are
bound to run into deficits even if they arrive as scheduled by their developers.
The amount of money invested and payed for each bitcoin mined varys
between ~260$ and ~560$ but generally is growing as the future mining
hardware is incoming.
Almost all plattforms i have seen lately as i already said wont run significant returns
for their owners having a certain safty margin in mind.
The timeframes for running the machines profitably are very small as well.
Around 3 to 7 months are not uncommon.
I propose to hold back your investments.
The race down the fabrication with of the ASIC world is to come to a slow down
within the next few generationsas the Mining ASICs meet with the state of the industry
production fabrication withs between 20 and 14 nm.
At that point i expect a more level playfield for mining operations and more stable
envoirment reenabling mid and long term investments into the mining market.