I'm glad you like it. This is one of those personal UX preferences that has you either one or the other camp. Am I right to assume you liked this from your past Opera use?
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.
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.
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.