XaoS provides a great learning experience for all fractal novices. The application can display not only the most well-known fractals (Mandelbrot, Julia) but also custom ones, based on your own formulas. Users can apply color filters in order to customize fractal appearance. One can activate the "autopilot", which will continually zoom into the fractal.
XaoS offers a great deal of fractal related information and an overview of its features in the form of replays; all this content is displayed interactively in the application's interface with playback control available for the user. You can learn about famous or less-known sets, the math behind the fractals and how you can apply filters.
The downside of XaoS lies actually in its austere layout. All controls are available from the file menu, hotkeys are displayed alongside any of the functions; you may find them only in the help files.
XaoS provides a great introduction into the word of fractals, but it is equally versatile. Users can perform solid guessing, dynamic resolution or bailout calculations. As a fractal enthusiast myself, I enjoyed the freedom allowed to explore a loaded fractal as well as the tutorials.