Anand Tech has taken a look at the AOpen MiniPC, it's somewhat a Windows-compatible version of the Mac mini:
It seems that AOpen has been working towards the creation of the MiniPC over the past year or so. First, we had their Pentium M desktop motherboards, followed by some Pentium M small form factor systems, and then they made the MZ855/MZ915 really small form factor design. These were all decent efforts, but I, at least, continued to think, "Can't anyone make a Windows-compatible computer that will compete with the Mac Mini?" Now, the answer is finally "yes", but there's more to it than that.