I was excited to sudden see this surprise in the patch notes, now I am the opposite here thinking, "How did they mess up such a simple feature?" The preview bar that pop ups is slow to work and actively delays changing tabs.(If it even attempts to switches tabs.) Additionally, I do not need the preview portion.

FLST: https://addons.mozilla.org/en-US/firefox/addon/fww-flst/

It just works. Tab switching is instant, no unnecessary preview, and it has never messed up remembering tab order.

I'm with you and cannot stand the way Opera does it but it also has a quick tab switching mode. I haven't encountered a single switch-with-preview implementation that didn't leave me with forced slowdown and delay of the action I was about to do. I also configure Firefox to not close the window when it's the last tab, which is hard-to-impossible to emulate in Chrome but is the default in Opera and Vivaldi.

Actually I like it from IDE's and text editors :)

As well as the alt+tab desktop behaviour