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.
Ideally I’d have both horizontal and vertical tabs, since its easier to glance horizontal tabs, but I think I’d get used to just horizontal after awhile.