Motion pictures actually look pretty fluid around 15 frames per second. B&W silent films were hand-cranked at 18FPS, and looked pretty good. Most were re-recorded to the standard 24FPS format to run on regular projectors, but that's why old silent films look like everyone is running around.
Usually film won't look jittery at 24FPS unless the projector is poorly maintained.
Some people can see the flickering of fluorescent lighting (60Hz), and usually those same people are also bothered by the visual artifacts created by the color wheels in DLP digital front projectors.
Most people can see the jumpiness of a 60Hz refresh on computer monitors, but with others it will give them a headache or eye strain. So most people raise the refresh rate to 72Hz+.
The light output difference with my previous Mustang was the same as low-to-high beams, which is no doubt what pissed people off (thinking that I was flashing my high beams at them).
For under $100 for the pulley and belt, I can see swapping in a new pulley. I just don't want the variable-light-output problems that I experienced before.
-Dean.