Summary: I have purchased this unit to use as HTPC. Installed 4 GB memory and SSD. Everything worked fine except every 2-3 hours computer freezes with high pitch noise. The only way out was a hard reset. Then it worked for another one or two hours, then crash again. Reinstalled OS(Windows 7), reinstalled drivers - to no avail. Crashes continued. Zotac support told me to return the unit - bad graphics card or motherboard. The good thing - return was without any hassle.
Summary: Threw in a fairly cheap 500GB HD and 8GB RAM, and I am pleasantly surprised. Installed Ubuntu 13.04, and runs extremely well. Some minor bios tweaks required, but running HDMI out to a 40' TV and 99% of what I need to run runs smooth as. Mostly using for TV/Movies currently (up to 720p works very well). Quiet, small, all the ports most people would need. No audio on the HDMI port (that I can figure out anyways!) Totally recommended though.
Summary: I bought the AD06 as a platform to be an ESXi Vmware host. I installed this from a USB thumb drive. The installation was painless. I then installed two Linux client boxes, one to host the email server, Zimbra; and the other to act as a file server. Everything sits behind a Cisco PIX 501. I work as a network analyst so networking and security issues come naturally.