since there are so many miners here and I want to buy ANTMINER S3 I'll post my question here. Is there a chart of multipool mining profitability in fiat over a long period of time (6-12months)? If not maybe you can tell me from your experience..
I want to know whether the current $1.6/100GH/day is somewhat stable and can be expected to stay that way the coming 6 months.
(I'm a newbie regarding mining, so with this miner I can use it for multipools right?

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I'd take some serious time learning more about bitcoin before you invest a cent. The difficulty changes after every 2016 blocks. Here is a list of the historical increases.
https://bitcoinwisdom.com/bitcoin/difficultyIn the last 6 months it has gone from ~3 million to ~19 million. SO NO WAY you will be making anything close to $1.6/100GH/day in 6 months.
thanks! I know about bitcoin difficulty and got burned already

I'm asking about the other coins since multipools mine the most profitable, which ever coin it happens to be. But there is no "profitability" chart of multipools over such a period of time.
I have been mining at multipool.us for several months. I haven't kept detailed records but can tell you that it now spends >95% of the time mining bitcoin directly, not any of the other coins. The way the pool works ensures that any of the more profitable coins will be mined until they are approximately the same profitability as bitcoin, so it effectively destroys its own market. I imagine the other multipools will have roughly the same effect.
The only way to beat the multipools is to mine newer coins before they get added to the pools, which is a bit of a gamble and isn't a set-and-forget option which I think is what you are looking for.
It is a circular system. You buy equipment to mine, it increases the network hash rates, so they increase the difficulty, forcing you to buy more equipment to stay profitable, all the new equipment causes them to step up the difficulty again, and make you buy more equipment again. Basically you are spending all your profits on more equipment to stay as profitable as when you started mining months earlier. All in all, the only ones making money are the equipment manufacturers and the power companies. The network hash rates is growing so fast now that you can't make enough profits to invest in solar/wind power to offset the power costs. Once you get into the loop, it is hard to just shut down $20-30K of mining equipment that has only allowed you to buy more mining equipment. Nothing in your pocket to speak of. Kinda sucks unless you have hundreds of thousands invested in equipment already.