Keep in mind that BeOS was released in 1995.
BeOS had pervasive multithreading and a slick UI. The BeBox had dual CPUs, a novelty at the time and many years before multi-core CPUs.
Linux was still very new, and didn't have much of a GUI at all (maybe basic X, but this was long before Gnome, KDE, Englightment, etc)
Mac System 7 didn't have protected memory or preemptive multitasking.
Windows 95 was brand new and while a big improvement over Windows 3.1, was still very prone to crashing.
^this, plus being able to play 3-4 quicktime videos at the same time smoked everyones brains around me. Using mac os 8/9 was a several times a day cursor freezing up and having to reboot. win95 was even worse
The one that blew my mind was you can drop a QuickTime movie onto each side of a 3d cube and they all played without dropping frames.
I think I'm remembering this correctly - couldn't you move the window while the video inside continued to play?
Yes you could! Windows did have (at some point) "show window contents while dragging" option, but it was quite slow at the time, and I don't remember if it supported showing (overlay) video content while moving or not.