Here are a few of the high points that TUAW is aware of:
The Mac name Using "Mac" in the product name was probably a bad idea. Psystar just re-named the platform to "Open Computer" instead.
Pre-installing Leopard It would seem that installing Leopard on non-Apple hardware is a violation of Apple's EULA. Virtualization vendors such as Parallels and VMware have already acknowledged this constraint in their product development; otherwise, both would offer VMs capable of running Leopard on any PC and not just on Mac OS X Server.
If you haven't yet checked out the discussion thread on Digg, I encourage you to do so. It's especially useful with its discussions about hardware limitations and hackintoshes.