Vivaldi is my new main browser and with it now having a calendar and mail support I've been able to stop using thunderbird too. Notes I have not used much yet but could potentially kill the need for qownnotes.
I had hoped feeds would allow me to stop using feedly as well but in its current state I hate it. No categories, you can't change feed update times on a per feed basis its universal and it adds unread feeds as a unread mail counter... why?!
Page tiling and web panels are also neat.
Pretty much all the new features can use some more polish, calendar notifications should require being dismissed or have a pinned alert icon otherwise its too easy to miss. Same with the countdown / alarm notifications. There are a few things I miss about FF but overall the transition has been good.
