With Windows XP, I found, as I expected, that there is no easy way to upgrade.
...I had to reinstall every, last application, fonts and drivers. ... The only version of Windows that can be upgraded without jumping through hoops is Vista. Even Vista, however, can only be upgraded easily from the same version to another or to Windows 7 Ultimate. [Mossberg had to reinstall all of his programs with Vista, so the few who suffered through that may not really have it easier.]
In stark contrast, Ubuntu was easy to upgrade. There's simply no comparison. Mac OS X Snow Leopard is also an easy upgrade. Just like Ubuntu Linux, all you really need to do is put in the DVD, make a few mouse clicks, and go have lunch while it runs. Once installed, both Snow Leopard and Ubuntu ran perfectly. That's more than I can about Windows 7. [typical Windows networking problems follow]
Unix just works and the more freedom you have the easier it is. With more vendor free software support on the way, the difference will grow."