I bought the ZBOX HD-AD02 about a year ago and it has been great as a HTPC. I just picked up the ZBOX Nano AD10 from Newegg on sale. A day later this starts making its way around the tech sites. I'll probably pick one up eventually.
While the Raspberry Pi makes for a great HTPC, its more of an appliance. The ZBOX series is a fully capable computer. Spec wise, its also much more powerful. I'll still be picking up a Raspberry Pi once ordering is open again though.
For those comparing this to a laptop you need to consider the AMD E-450 SoC. I bought an HP netbook with a E-450 and after the holiday discount and a promo code it cost ~$400. The cheapest laptop I see listed on Newegg running an E-450 is going for $350. Also consider the form factor. This is much smaller than a laptop or netbook.
You can't please everyone. This device meets all the needs I have for an HTPC (SSD in case I ever have to reboot it will feel like an applicance, HDMI, Toslink, Gb networking, IR, a video solution that provides perfect playback of video, and a very small formfactor) and the added elegance of packaging is a bonus. To get something like this built will cost me at least $300 in parts so I'd be willing to pay a little more for a more polished and manufactured feel.
I bought this device. I'm currently tooling abut with using it for XBMC in Ubuntu (I'll probably give OpenElec a try at some point). So, all my points are for this device in context as an HTPC, and in particular working with XBMC, mostly in Linux.
This thing can indeed play all the way up to 1080p video from blu-ray ISO perfectly smooth, so long as you do a little work to make sure its using 3D acceleration. In Linux it supports non-TrueHD surround sound from the HDMI. Dolby TrueHD and DTS Master audio aren't working yet in Linux, due to a driver issue they're working out with ATI/AMD.
They work in Windows, but in Windows I've found it doesn't boot to XBMC nearly as cleanly. Also you have to load drivers for USB3 (which Linux can use out of the box), and samba fileshare browsing speeds on Windows 7 were abysmal, compared to nfs on Linux.
The remote works in Windows once you load the drivers from it (which yes, you have to load the driver installs from CD or elsewhere to a USB for Windows, unless you have a USB CD drive).
I'm working out how to get it to work in Linux.