Windows Vista vs Windows XP
Windows XP and Windows Vista are two Microsoft operating systems for consumers, supported and maintained by Microsoft. For new computers, people generally choose the newer Windows 7 or Windows 8 instead.
 Resource Consumption
Windows Vista consumes much more resources than Windows XP. What this means is that more memory (RAM), hard drive space, and processor speed are required to achieve equal performance when using Vista.
Windows Vista incorporates a number of new security features that were not originally part of Windows XP. Some of these features have been backported to Windows XP by Microsoft, while others are particular to Windows Vista.
Used correctly, some of these features provide improved security practice on the part of the user, though doing so imposes an inconvenience overhead that many users find unacceptable. The canonical example of an inconvenient implementation of a security feature in Windows Vista is User Account Control, which many users simply disable because of its user-hostile operation.
The above applies to the default state of a recently installed system. Certain security features of Windows Vista interfere with the operation of third-party software that may provide similar security functionality, however, and in some cases these alternatives are regarded by many as better for purposes of providing strong security for the system.
There are arguments against the effective security of new Windows security features, including both some of those incorporated into Windows XP and those specific only to Windows Vista, on the basis of their effects on user behavior. Because fundamental security characteristics of the system such as complete privilege separation have, as of Windows Vista, still not been integrated with the core system architecture, it is believed by some that the security feature facsimiles of such functionality may lull users into a false sense of complacency that contributes to poorer security practice on the part of the user. This is a purely social argument, however, and does not directly affect the security of the system itself in terms of technical design characteristics.
In the long run, only experience and heavy testing "in the wild" will provide a significantly trustworthy comparison of the relative merits of security profile for Windows Vista, as compared with that of Windows XP. For now, however, it appears that Windows Vista provides slightly improved technical security than Windows XP in its default configuration (without any third-party security software), assuming a reasonably intelligent, security-conscious user.
Windows XP is faster than Windows Vista.
Windows XP is installed on more computers than Windows Vista.
Windows Vista Business Edition and higher is glitzier than Windows XP. This is mainly due to the Aero theme which takes advantage of advanced video cards to make windows semitransparent and have 3D animations.