Quote from: torusJKL on December 05, 2013, 12:55:29 AM

Quote from: dzarmush on December 05, 2013, 12:29:11 AM

There are lots of group buys for miners with delivery date somewhere next year. But according to these calculations even a couple of weeks matter http://www.vnbitcoin.org/bitcoincalculator.php

Is there something I don't understand, or most people doesn't know about difficulty growing? Or everybody who takes part in group buys for Q1/Q2 miners believes that bitcoin also going to grow with difficulty increase? The last month of Q2 is June, what if miners won't be delivered until then?

I'm sure they know about the difficulty increase.

Bitcoin going up in the price is not a valid argument for ROI in mining.
If you want to get ROI with a miner then it will need to mine more bitcoins then what you would have been able to buy at the same time you bought the device.

Otherwise it is better to just buy bitcoins and don't mine.

Torus, is there an equation form of this somewhere? I can visualize these things better like that.