There are a couple of demo videos for the Juin Tech AB-1. Might be worthwhile for delicate equipment. I haven't heard of any problems from cell phones, action video cameras or lights mounted directly to handlebars or frames.

I'd consider something like that only if it acted like a Steadicam for action video cameras on chipseal and similarly rough roads. A simple spring won't do that. It would need to be an adjustable weighted device, and practical only for some situations. Even the cheap plastic clamp on mounts included with my Ion Speed Pro are good enough for smooth pavement and even some crushed limestone chat trails.


Vibration test demo:

Here's a demo video of the Juin mount with a GoPro. Looking at the background, it doesn't reduce vibration effectively enough to interest me. However it might minimize damage when mounting regular cameras that aren't designed for rough use, especially those digital cameras with telescoping lenses that are easily damaged or knocked out of alignment.