The jump from version number 3.8 to 4.0 comes with a few massive changes for Vivaldi users, starting with the three features still in Beta status: Mail, Calendar, and Feed Reader. This update also intros Vivaldi Translate, three interface layouts to choose from, and more. The Android update is also moving to version 4.0.
https://www.notebookcheck.net/Vivaldi-4-0-now-available-with-integrated-email-client-and-feed-reader-calendar-and-more.544344.0.html
No youtube downloader and no interface flexibility pretty much kills it.
Vivaldi is the best, theres no point to even begin to think twice. That aside, main reason to use Vivaldi, is it's not chrome, edge or firefox. Sell that browser and were gonna live once again in the dark ages.
Vivaldi is constrained by Chrome. Any extension is limited by it.