PopBox v8 is basically the same as PCH A-300, but w/o internal hard drive capability, no NMT user apps (not that I find anything useful), and no Blu-ray ISO full menus (only BD lite). But, like the A-300, it supports YAMJ/Eversion jukebox. Boxee's benefit over PopBox/PCH and Dune are nice out-of-the-box UI, built-in movie/TV jukebox (as opposed to 3rd party) and Internet apps, especially premium apps like Netflix and VUDU, which don't exist on the former.
Re: my Boxee Box-es, no I put them to sleep, not on all the time. But, technically, I've read they're basically the same, use the same amount of power, etc.
HD Media Keen Videosaurus