4. An Intel Mac won't run all Mac software (including Apple applications) natively-the Mac used to rely on the Power PC processor, and programs for that processor will not run on Intel CPUs. Only programs that have been ported to the "Universal" architecture will run on Intel; others must be run under emulation (Apple includes emulation software called Rosetta with OS X), with the associated degradation in performance (and loss of productivity), or else upgraded. Consequently, a "simple" hardware upgrade from an older model to an Intel Mac can end up costing thousands of dollars in software (Adobe Creative Suite Design Premium 3 upgrade, for example, is $599)-if you can get it. Microsoft Office 2004 is not universal; it runs in emulation mode on Intel Macs, and some components such as Virtual PC don't work at all. Although Microsoft says the next version of Office for Mac will be universal, it says it will not include Virtual PC. Apple's own Appleworks 6.2 has not yet been ported (although, to be fair, the Appleworks User's Group says it runs without degradation on Intel), and an upgrade to a compatible version of Final Cut Studio will set you back $499.

5. Because the Macintosh market share is so small (5.6 percent in Q2'07, according to IDC), the population of Mac support people is equally sparse. This means it's harder to find qualified people. Desktop support personnel with Mac skills can come at a high price; for example, several New York City jobs on Dice.com offer $60,000 to $70,000 (the median desktop support rate for the area, according to HotJobs.com, is $50,886), and also require Windows and/or Unix skills. Mac supporters will no doubt point out that the systems don't need much support, but the fact remains that when they do, there had better be someone available to deliver it.

6. The small Mac market share also means that some vendors don't see the value in making their products, both large and small, Mac compatible. Even if a hardware device is plug-and-play, its accompanying software may only come in a PC version, providing less functionality to the Mac user. BlackBerry Desktop, for example, was developed for the PC only, and it took third parties to develop Mac synchronization software for Pocket PCs. The cost of parallel development to make products compatible often also means that the Mac versions are more expensive than their PC counterparts.

7. Some websites requiring online input won't talk to Macs. Even the U.S. government has dropped the ball; its grants.gov site originally didn't permit application submissions from the Mac, and even now, according to the site, the "early release" software is prone to crashes with data loss and won't run on any versions of Mac OS earlier than 10.4.6 (don't pout-it doesn't work at all with Windows Vista or Office 2007). The cost here is that of a PC, if you don't want to risk the aforementioned software hazards. The opportunity cost associated with being prevented from interaction with these sites must also be considered, as must possible repercussions if the incompatible site is one upon which your business relies, perhaps for regulatory or financial services.

All this is not to say that the Mac will never make it into the enterprise. The Apple world has been becoming less insular each year, and the Mac market share has been growing. But right now, it hasn't quite achieved that critical mass that will make it an economical choice for mainstream business.

Lynn Greiner is a freelance writer who really has nothing against Macs - the editor made her do this. She is also a vice president of IT for a multinational corporation and an award-winning technology writer.