If you exclusively use vertical tabs (either with CSS or another way), how is it? Did you miss horizontal tabs at all?
I’m trying to switch to Floorp right now from Firefox, where I have both the regular horizontal tabs, and a flat vertical list with the Tree Style Tab extension. I use the later a lot, and while I could keep this setup in Floorp, I like that the vertical tabs can be native instead of using TST. However, it just feels weird to not have horizontal tabs. I think I might miss seeing a bunch of my tab titles at a glance with it, but I have to use it more and see how I feel.
I don't miss it. I use collapsible vertical tabs in Firefox with Sidebery + custom userChrome.css like this (the flickering only happens in the screen capture :/).
In fact I was really tempted to use Edge before I found a usable vertical tabs setup for Firefox. And now after over a year I cannot comprehend why vertical tabs on desktop (that is, wider than tall) format displays is not the default for all browsers.
I've been using vertical tabs on Firefox with a neat CSS style that makes it look part of the browser in a beautiful way. It was weird at first, especially because I kept dragging my cursor to the top of the browser, searching for the tabs but I eventually got the hang on going to the left. I find it great tbh, can't go back to horizontal now.