[Zecc]

No idea what Edge's vertical tabs look like, but I like vertical tabs in Firefox because it lets you have simultaneously on screen a ton of open tabs without reducing the tab's size.

I don't care about the loss of horizontal space most of the time. I have a 16:9 screen and most web pages grow vertically anyway.

As a matter of fact I use a vertical Windows taskbar as well, since it lets me have many applications open while still displaying their window titles. It's not usual for me to have 5 file explorer windows open, and their taskbar buttons won't combine.

[kitsunesoba]

Yes precisely, standard tabs get unusable quickly. I know some people can deal with dozens of tabs shrunken down to the size of a favicon, but I can't.

I wish vertical tabs were a standard option on all browsers, especially on Firefox where you need userchrome hacking on top of an extension to get something usable — userchrome css is deprecated and going away, which means integration deeper than is offered by extensions will be necessary in the future.