Heavier weight means the record should be more durable and be less susceptible to warping over time. Heavier weight is probably a general indicator of a higher quality product, but assuming no warping otherwise, sound quality will be determined more by other factors on a case by case basis.
In general, I think heavier weight vinyl in new issues is designed to appeal to the target market of vinyl affectionados that will appreciate a more heavy weight product and be willing to pay for it. But there is probably a good chance that on a case by case basis, standard issue vinyl recordings from yesteryear that were made in the time when records ruled for most may sound as good or better.
In general, I think heavier weight vinyl in new issues is designed to appeal to the target market of vinyl affectionados that will appreciate a more heavy weight product and be willing to pay for it. But there is probably a good chance that on a case by case basis, standard issue vinyl recordings from yesteryear that were made in the time when records ruled for most may sound as good or better.