I've been doing some digging looking to get into mining. KNC seemed best option in terms of power/delivery date/price. However, I've ran some numbers:
Jupiter unit(400GH/) $4,995 + 20% VAT(most European countries have similar VAT bit lower or higher even) = $5,994
+
Hosting(I've considered it because it includes PSU, you get it earlier than others, it's supervised, no risk of faulty unit, having to send it back, power costs included, high uptime % n so on)
12 Months Jupiter hosting = $ 3,960 + 20% VAT= $4,752
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Total(Jupiter unit+ 12 month hosting)= $10,746
Ok so far so good...Now the hard math begins. Here are the variables:
12 month mining period
400Gh/s Hash power
10.746$ total investment
95% uptime(probably optimistic)
1,6853% difficulty increase/day
ETA for mining unit: 2.5 months(probably optimistic)
Exchange rate for BTC 150$
KNC Pool mining fee 1.5%
Power cost: 0 (since it's included in hosting package)
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Results:
Initial Coins per Day: 2.16535
Initial income/day: 384,8 USD
Reduction/week: 12,41%
Break even including difficulty change: Never
Net profit/loss: -5309.7 USD
Of course Bitcoin price can get much higher but then again it may not and ETA for mining units may be delayed, the downtime can be smaller than 95% so on and so forth.
Assuming all the variables above stay the same, this setup could be profitable at a Bitcoin price of $300 starting from day one. With a $300 BTC price averaged on a 12 month period, one could earn a net profit of $126,6.
Again KNC seems one of the good deals out there. Others like BFL are even less profitable.