BeOS was ahead of its time, that's for sure. One thing it did exceptionally well was multitasking. Even if you had a intensive task running in the background, you would never notice any lag whatsoever in the GUI. Windows/Linux/etc on the same hardware would lag horribly when doing the exact same tasks. I understand many aspects of the OS and GUI toolkit was multi-threaded (as BeOS was designed to run on, and take advantage of, systems with multiple cores). To this day there is no OS that handles multitasking as gracefully as BeOS did. I still remain disappointed that it did not see much success as it had so much potential.