Vertical tabs made a lot of headlines when they hit nightly months ago and they were a bit jank, never quite feeling like they're part of the browser. After updating to 133.0 though, turning on the sidebar revamp (sidebar.revamp) and vertical tabs (sidebar.verticalTabs) in about:config now work so well!
There's no blank space hovering between the address bar and top of the window, tab previews work well on hover. Finally I can ditch Sidebery and it's pulled me back over from flirting with Zen and I'm using this setup full time now <3
It is nice! A couple of things kept me from committing to it though โ mainly the lack of 1Password integration on Windows (I think this is 1Pasword's fault, not the Zen dev's), the ugly app icon (which is changing at some point in the future), but more than anything else it's just changing and experimenting with new features at the minute, with new updates posted almost every day and features shifting while you're using them. Which is fair enough for developing software, I'll just come back to it down the line.