Apple does have a usability advantage of Linux, and OS X is undeniably sexy. However, as some Linux distributions look to emulate the Windows GUI and manufacturers sell budget systems with Linux pre-installed to eliminate hassles, fewer potential /switchers may be able to justify Apple's price premium.
It's important to note that Slate is owned by Microsoft. Still, the article makes some pretty compelling arguments for Linux taking over the number two spot on the desktop. Content creation professionals will no doubt flock to the new G5s, but will Apple's eMac and iMac lose out to much cheaper Linux-based alternatives?