Let me first state that although MacOs is a piece of crap, at least it is a very shiny and sweet scented poo. Windows on the other hand is crap from the surface appearance (the aesthetic of the windows etc) right through to the underlying form (the core OS services). Read Zen and the Art of Motorcycle Maintenance for more info.

1) Mouse update frequency and syncronicity.
2) Windows has many thousands more viruses.
3) The "facade" of Windows3.1 and then Win95.

1) Mouse update frequency and syncronicity.

On the mac, it depends on you monitor verticle refresh frequency (as set in the montiors control panel) and could anywhere from 50Hz (Only on my Amiga MacOs PAL emulation) to way up 70,80, 100Hz. The mouse is totally smooth and tracks beustifully as a result.

Unfortunately, Windows 3.1 and Win95 both have very dumb thing called a "software polled" mouse pointer update. The CPU sends the initiative to check the mouse using a pre-emptive time-scheduling facility (yes even on Win3.1 - it's called an interupt). But it wasn't synced to the monitor like the MacOS, Amiga Workbench, and The Atari Pointer, and as a result the pointer jerks and bumps across the screen. The software polled/timed approach is also used on X Windows (Silicon Graphics also suffers the same problem), WindowsNT, and OS/2.

An Example:

Mouse movement = 75 pixels
Screen Refresh Rate = 75 Hz

On the Mac:
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, = smooth movement
On Windows: (assuming a mouse refresh of 51, which is good for windoze)
0.68 - a fraction comes out as
0, 1, 1, 0, 1, 1, 0, 1, 1 = jerky movement
0.68, 1.36, 2.04, 2.72, 3.4, 4.08, 4.08, 5.44 you get the idea, its very very jerky.

1. Shutdown Mac = Drag and drop mouse (special/shutdown)

Oops, I got bored with this page and forgot to finish it. But you get the point. For more on this topic try: WhyMac