I also had not heard of that hardware platform. Has anyone heard anything (good or bad) about it?
Funny you should mention those. I ran across them a few days ago while I was researching ARM Linux appliance hardware. I can't really say much about them in particular but they're built around Freescale hardware which seems to be the trend in embedded Linux boxes. IIRC Freescale has primarily been an industrial controller company in the past which means they have lots of experience designing and building hardware on this scale.
The problem I would have with any sort of DIY ARM-based appliance at this point is it just doesn't make a lot of sense for me as an individual user. The second hand PC market is currently flooded with off lease Small Form Factor PCs which typically have dual core CPUs (either Core 2 Duo or AMD 64 x2), SATA, and both PCIe x1 and x16 slots. In fact that's what I'm planning to use to build a set-top box and 1 or more appliances for my home network.
For $50 or less I could get a HP SFF box with an 80GB HDD and onboard ethernet. Spend $40 - $50 on a nice Intel PCIe x1 wireless card with a high quality antenna and another few bucks on a second wired interface and I can turn it into a spectacular appliance for my home network.
If I get one of the newer models which are frequently sold with 200 - 300 GB hard drives all I need is a relatively cheap video card and remote plus a couple USB ATSC tuners (and maybe a sound card) and it should make a nice little DVR. SFF boxes are already decent enough looking to sit in the living room and since ATSC is MPEG-2 all the video card really needs to do is provide DVI and/or HDMI for the TV.
Now if I were building a business box I could see going with ARM but I'd be looking for something along the lines of a SOB (System On a Board) setup to build a cheap and low cost Beowulf cluster out of.