The most obvious reason to choose PCLinuxOS is that the hardware required for running PCLinuxOS is significantly less taxing on older computers. Using PCLinuxOS with the MATE desktop provides a nice clean looking desktop environment without giving up any features that you may find within Ubuntu.
Moreover, If you are using Windows XP then you are not the sort of person who likes change. (where computers are concerned) PCLinuxOS is a rolling release distribution and it really is a case of install once and once only. All a PCLinuxOS user has to do is let the updates run and the system will constantly stay up to date.
Besides, the MATE desktop within PCLinuxOS looks very Windows XP like and the transition between Windows XP and PCLinuxOS isn’t all that difficult. Many of the features within PCLinuxOS are available using a similar point and click approach to Windows.
PCLinuxOS has all the features and apps working from the initial installation and it is likely that people using Windows XP would like to do as little as possible to get things working.