In 1999, for instance, Gistics released a landmark report analyzing Macs and PCs in terms of return on investment (ROI). Gistics' study was limited strictly to the publishing, graphics and new media fields. Among many other findings, the authors concluded that Mac creative professionals were producing $26,000 more each in annual revenues for their employers than their Windows counterparts.
Some six years later, soon after the advent of OS X, computer security expert Winn Schwartau created a widely publicized tool geared to helping companies in any industry measure the TCO of Macs versus Windows PCs. Schwartau emphasizes that results from the tool can vary considerably from one business to the next. But at his own small enterprise—then known as Interpact and now dubbed The Security Awareness Company—three-year TCO turned out to be twice as high for Windows than Mac.
It is a good article and well worth reading; in particular it highlights—especially on the issue of volume licensing—the different business plans of Apple and Microsoft. Plus, it is actually a good, solid article unlike the one that gives Seven Financial Reasons Not To Use Linux In Enterprise, which is not only poorly written but seems to assume far too many worst-case scenarios.
Disclaimer: thanks to Jackart (who does this stuff for a living), in February, your humble Devil realised a dream and he now owns shares in Apple Inc.