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.