if you guys all consider that, the MH/W is a very important value, we could pay more effort on energy consumption optimize.
I might be alone in this, but shipping times and keeping the cost down is more important to me than power savings. That's just my opinion, though.
It really comes down to how much power is saved. If we're talking 25 watts for two months extra time, probably not worth it. There are always options around the power issue including hosting your farm somewhere else where power is cheaper.