I'm not op, but these are some things that I appriciate about Vivaldi:

• Mouse gestures that work anywhere in the window with different options based on what I start the gesture on (eg. Right clicking on a link and dragging down opens the link in a new foreground tab {dragging down then up opens it in the background} but doing so on empty space opens a new tab)
• A scrollable side bar for tabs instead of the horizontal one that is standard (not in addition to or requiring hacky workarounds)
• The ability to minimize tabs or send them to the bottom of the cycle order (this needs to be able to be done with mouse gestures)
• The ability to easily highlight parts of a link so that I can copy part of the text (Vivaldi highlights with a click and drag and drags the link on a click, hold and drag; Firefox doesn't appear to do either)
• Not having to worry about third party extensions security issues or having this core functionality stop working because the extension maintainer has to update it for the new browser version.
• The fact that it just works with minimal configuration

Unfortunately I am looking for alternatives to Vivaldi since Google has decided to kill quality web browsing on Chromium browsers. Much of the web is virtually unusable to me without a tool like ublock quieting things down to work past my sensory processing issues. At times it is hard to think that the majority of web devs have anything but distain for disabled people.

I do use Fennic on Android (with ublock and darkreader) because Mozilla decided to block access to about:config in the mobile version and I have yet to find another way to always force pages to load the desktop version. (Mobile versions of sites disable most of the built in accessibility options like the ability to zoom)

The settings I set in fennic if anyone is curious:

• browser.viewport.defaultZoom (set a sane default zoom)
• browser.viewport desktopWidth (say that the screen is large enough to not trigger CSS mobille layouts)
• general.useragent.override (work around browser sniffing; I've yet to find an extension that actually works for this)