I'm still a little wary about Atom... Much of the power increase would simply come from a higher clock rate; clock-for-clock, Atom doesn't tend to score as big a gain over ARM as other current x86 architectures, such as Nehalem/Sandy Bridge, AMD's Stars, or even Bulldozer.
That, and many ARM CPUs are claiming sub-watt TDPs... While the CPU tends to be secondary to the screen and wireless in terms of power consumption, it could still make an impact, so I have to wonder a bit about the battery life. Little word on precisely the core used for Medfield, (since the name appears to apply to the whole SoC, and not just the CPU) but I'll hope, for Intel's sake, that it's the MID counterpart to Cedar Trail; they'd managed to scrape the 1W TDP line there.