The people that have opted to pay 12 months upfront @ $330/mth. hosting, you can consider that a $0.60c per kWh power cost in your calculations.
From what I calculate, I get the following:
$3960 (Hosting cost) - $150 (At least $150 for the PSU you are NOT having to buy) - $150 (approximately what I paid for my Saturn shipping, which you don't have to pay). So...
$3960
-$150
-$150
________
$3660
(($3660/ 12) [months] / 30 [days])/24 [hours]
$3660/12 = $305 price per month
$305/30 = $ 10.17 per day
$10.17/24 = $ 0.4236 per hour
And that price is without counting cooling cost and internet connection; and I'm sure they would have backup internet, and backup power (I assume, as any decent data center would), which most people do not have.
I personally wouldn't (and didn't) go for hosting, but I can see why someone might. You don't have to worry about anything. Just sit back and watch the satoshi's come in.
Also the fact that you have to get a minimum of 6 months at an even higher price.