Our free CMS [1] was featured on Product Hunt 1.5 years ago, after being posted to Designer News by someone, and got #1.
We were not actively involved in the posting, but it had a fantastic effect on our user base, we went from 1600 GitHub stars to 3k+ thanks to it (now we're close to 6k), plus it allowed a snowball effect on Twitter and other websites, that lasted for weeks.
The whole "happening" was described in https://getgrav.org/blog/grav-reaches-3000-github-stars
I wouldn't know how to post it on PH myself and get a similar effect. The product was discovered and featured by a prominent hunter that found it interesting / worth featuring, and had success thanks to that.