I've owned an MC-1 since Dec 01. I have to say that I love it and I hate. From a hardware point of view, it has a lot going for it. It has both analog/digital input/outputs, a decent remote, a crisp S-video out. It does a marginal (but mostly acceptable) job at ripping, looking up tracks, looking up album covers. Both my wife and kids can operate the MC-1 (definetely a plus in their books).
My problem with it is that its interface is very sluggish (but usable). The external software to download MP3 is so buggy that it is completely useless. The internal MP3 encoder is very weak (it doesn't support VBR and it occasionally introduces some very bad artifacts that I don't hear on my PC ripped tracks).
I've had to send my unit in for repair (a corrupt file system I think). Compaq is totally clueless about this product. Compaq's customer support was a triple threat - clueless, rude and condescending. There support wasn't sure if it was a computer or an Ipaq hand-held MP3 player. It took about a week (and several hours on the phone) to get someone on the line that had heard of the product.
It's really too bad. The hardware looks decent and well thoughtout. The OpenGlobe software, on the other hand, doesn't appear to have been tested before it's shipped. Lots of potential ruined by poor software.
All in all, I'd recommend staying away from the MC-1 (even at $299). If you want MP3 audio in your stereo rack go buy a Turtle Beach Audiotron.
Oh, and to add one technical detail, the OS is VxWorks.