Depends on the model of each one. That said, you're not running it to be profitable, if anything it's a lottery ticket. At 40 watts for the 100 version, it's like a light bulb. Less efficient than the current bitaxe stuff, but it still costs basically nothing to run. 

If you're deciding between them, I'd venture to day esthetics may play more of a role in that decision than efficiency for certain people.