One good feature is that multiple windows of Words or Spreadsheets take up no additional memory except for the contents. The Applix system returns memory used in loading windows, and gracefully allows the swapper to minimize the footprint of modules not in use. There is only one process, axmain, which adds shared libraries as needed. The library space is not reclaimed until the axmain program is exited, however, although this is not a problem unless it causes you to run out of swap space. In general, integration with X is also quite good.
Windows pop and disappear smoothly and the display repainting is smooth.
There is a preference option to allow the Window manager to handle focus control, but this did not function properly on my setup. I use 'focus follows mouse' on FVWM 1.24, and although it did indeed change window focus, the window would not come to front unless I clicked on the title bar. I did see one X glitch, when I loaded Applix Presents and switched to another one of my virtual screens before it loaded. There was a ghost image of a set of dotted lines on the original virtual screen. Several commands caused artifacts to appear on the screen.