More efficient, though depending on what your plan is efficiency will be less important than power consumption. Battery power would be a good deal harder with those.

Like anything, you've got to pick the right tool for the job.

It's pretty much an updated version of the Dreamplug, although I'm going to miss the GigE.

The Pi (Model B which all the new ones they ship are), is 512MB RAM.

Shared with GPU, btw.