I think that is primarily a PC (running Windows XP), so I think of it like a laptop with knobs. The processor is considerably less than what I run in my PC now, although it would probably perform better due to lack of lots of other services, etc.
There are some similar solutions here:
http://www.openlabs.com
However, with these I'd be giving up my large monitor, computer keyboard and mouse for editing in favor of portability. I'm kind of wishing in the other direction, where I could have something like a Ti Desktop or Snow (or actually many of them if it were cost effective enough) which I can control through my host.
But I think the Rhizome, Neko etc. probably don't have latency issues.