Quote from: Francisdoge on December 31, 2013, 02:32:51 AM

I know I'm missing something really obvious, but according to calculators, a 550 GHS miner will produce ~$5219.66 a month.

10 btc ~ $8000

Even with difficulty going up of course, how is this a bad business ?

It depends on your assumptions.
A 550 GH/s miner might produce $5219.66/month at the current difficulty, but the difficulty can go up every 10-12 days.
And that's not counting all the ASIC that's supposed to be released in the near future.

However, you should also consider that everyone in the mining forums have a vested interest in preventing more miners (since it impacts their return).

The question you should ask yourself is whether you can make make back the 10.65 BTC with the Jupiter you are getting.
And whether you're willing to take the risk of something happening to your unit (ie, its defective), or your electrical power (maybe your unit will be what causes your distribution transformer to finally die).