

All gimmicks!  Stick with plain 'ol carnauba wax that's non-abrasive.
Eagle 1, Meguiars, Turtle Wax, and a few others are good examples.
The colored waxes just color in the scratches so they're not so 
apparent.  The better approach is to buff minor scratches completely
off with a cleaner/mild abrasive.

Never tried Liquid Glass, although I still have this sample they sent
me a few years back. 