Is that $500 or above Carnauba Wax any good?

Any Carnauba Wax or basically any final layer that you apply is merely a form of protective cosmetic.
It does not correct your paintwork's flaws.

As to whether a $500 and above Carnauba Wax is any good, it fully depends on the quality of your paintwork, and the extent+quality of surface prep work (aka compounding and polishing) that has been done on that paintwork.

On a brand new Mazda (example) imported from Japan, if only a mild polishing is done, and topped with super premium Carnauba Wax, you won't be impressed. On the contrary, on a new VW or BMW, you'll see a much more impressive result.

The lesson here is:  Your wax or final layer contributes the LEAST to the final results.
It's all in your surface-prep (eg: sanding, compounding, polishing etc)
It's 100% identical skincare.
Your surface prep is "skin treatment/skin correction". Once your skin is looking at its best, then its time to progress to using the best "cosmetics" (waxes, sealants etc) you can afford. Get your "skin" right first.

If the paintwork quality is average or above average, and extensive prep work has been done, you've already achieved close to 90% of the final looks, and any quality waxes or sealants will provide that last 10% in terms of richness, gloss and optical depth. No wax, no sealants and no coatings can serve as a "magical last layer" that'll turn an average quality paintwork (+ simple polishing) into a show car look that'll turn heads. 90% of the final looks will be determined the extent of the surface prep and how your surface prep were done.

Most synthetic waxes (eg Meguiars NXT) and natural carnauba waxes (eg Swissvax, Zymol etc) tends to darken the colour, which enhances the ILLUSION of vibrancy, depth and gloss. This is especially great on dark colours and black.

 However, IMO, on silver, white and other light colours, I don't want any waxes or LSPs that has a "darkening/richening" effect, as they tend to make these colours appear less bright and appear dull, without the bright "popping" effect. I never use Carnaubas on light coloured cars or pearl finishes. On such whites, silvers and light colours, you could try an average of 3 layers of a great synthetic sealant that doesn't change the colour at all (eg: Zaino Z2Pro, Jeff's Werkstatt, Klasse Twins, Duragloss 105, hundreds of Jap synthetic sealants, Turtle's ICE etc).

 Certain synthetic waxes such as Collinite 845 is also superb on whites, light colours....and especially silver. The above approach makes the silver and white look as "bright" as possible with no darkening effect. These colours will look vibrant and reflective, giving the car a sharp look.