I switched to Vivaldi a year or two ago after using Firefox as my main browser for the longest time. I've considered switching back, but every time I run up against several features in Vivaldi that I am just not ready to part with yet:
1) tab stacks,
2) the ability to save and reopen an entire session,
3) a page load progress indicator in the URL bar,
4) using Ctrl-F highlights the position of all matching locations in the page in the right-hand scroll bar, and
5) the window panel, which keeps track of all closed tabs and windows so you can reopen everything if you accidentally close a window.
Some of those are small perks, and some of them are major. I'd love to see Firefox implement some of them.
1) tab stacks, 2) the ability to save and reopen an entire session, 3) a page load progress indicator in the URL bar, 4) using Ctrl-F highlights the position of all matching locations in the page in the right-hand scroll bar, and 5) the window panel, which keeps track of all closed tabs and windows so you can reopen everything if you accidentally close a window.
Some of those are small perks, and some of them are major. I'd love to see Firefox implement some of them.