Migrated from Tampermonkey after learning that it was closed-source (and some other questionable privacy practices). Violentmonkey works great! All of my scripts ported over with no issues.

I've been using ViolentMonkey since always, love it.
One think which puzzles me is that the add-on appears once in a while here (as now) within search for updated extensions (sort=updated&type=extension) even though this latest 2.13.0 version is over a year old ((May 4, 2021) so why not be it updated for true?
NOTE : other non-updated add-ons appear in (sort=updated&type=extension) ... which may bring them a deserved boost but which does definitely not correspond to what is universally understood by "updated" :=)

Works just fine for my own scripts and seems less complicated and more intuitive than the original GM.

a good quote:
If you need compatibility with old scripts your best choice is Greasemonkey. If you need it for modern scripts or to write your own Violentmonkey is fine. Avoid Tampermonkey, they are not to be trusted (proprietary license and analytics)[1].

[1] https://www.reddit.com/r/firefox/comments/6hs59w/tampermonkey_has_google_analytics_enabled_by/